tbuckley/cabot-search huggingface dataset:
Abstract 18454: Calcium Calmodulin Dependent Protein Kinase II delta Modulates Cardiomyocytes Passive Stiffness by Phosphorylating Titin Spring Elements
Authors: Nazha Hamdani, Judith Krysiak, Michael M Kreusser, Benjamin Franzel, Dirk A Wolters, Lars S Maier, Markus Krúger, Johannes Backs, Wolfgang A Linke
Journal: Circulation (2012)

Background: High diastolic stiffness of the failing heart can result from altered cardiomyocyte mechanical properties. Cardiomyocyte passive force (F passive ) is attributed mainly to the mechanical properties of titin, particularly isoform composition and phosphorylation. Titin can be phosphorylated by protein kinase(PK)A or PKG at the N2-Bus, which decreases F passive . However, PKCα phosphorylates titin's PEVK-region, which increases F passive . Whether other kinases relevant for cardiomyocyte function phosphorylate the titin springs has been unknown. Aim: To investigate whether Ca 2+ /calmodulin dependent protein kinase IIδ (CaMKIIδ) phosphorylates cardiac titin and affects cardiomyocyte F passive . Methods: Cardiac titin phosphorylation was assessed in CaMKIIδ/γ double knockout (DKO; n=8) and transgenic CaMKIIδC overexpressing mice (TG; n=6). A SILAC-DKO mouse was generated for quantitative proteomics in vivo . Cardiac titin separated by titin gel electrophoresis was also studied for phosphorylation sites using MudPIT mass spectrometry. Recombinant wildtype (WT) and mutant fragments of human cardiac titin were expressed and phosphorylated in vitro by CaMKIIδ. F passive of permeabilized isolated WT, DKO and TG mouse cardiomyocytes was recorded between 1.8 and 2.4 µm sarcomere length before and after CaMKIIδ administration. Results: Total titin phosphorylation was reduced in DKO and elevated in TG compared to WT hearts. CaMKIIδ treatment of cardiac tissue ex vivo increased titin phosphorylation. A CaMKII-dependent phosphosite was identified within the N2-Bus (S4062) by MudPIT and two phosphosites within the PEVK-region ( T12007 and S12022 ) by SILAC. Western blotting using phosphospecific antibodies against these sites in cardiac tissues or recombinant WT/mutant titin constructs confirmed that CaMKIIδ indeed phosphorylates these 3 sites. F passive was elevated in DKO and lowered in TG, compared to WT cardiomyocytes. Administering CaMKIIδ ex vivo lowered F passive in DKO but did not affect TG cardiomyocytes. Conclusion: CaMKIIδ phosphorylates the titin springs , thereby lowering F passive . Reducing titin-based stiffness through CaMKIIδ-dependent phosphorylation of titin N2-Bus and PEVK may benefit diastolic function.
Abstract 18280: Mechanosensitive Trpv4 Channels Mediate Cardiac Myofibroblast Differentitation
Authors: Ravi Adapala, Dan Luther, Supriya Shah, J Gary Meszaros, William M Chilian, Charles K Thodeti
Journal: Circulation (2011)

Cardiac fibroblasts play critical role in cardiac remodeling and during development. Cardiac remodeling following myocardial infarction involves the migration, proliferation and differentiation of cardiac fibroblasts into hypersecretory myofibroblasts. Myofibroblasts facilitate wound repair in the myocardium by secreting and organizing extra cellular matrix (ECM) and fibrosis. However, the molecular mechanisms involved in myofibroblast differentiation are not well known. Because the infarcted/ischemic myocardium is known to undergo mechanical stretch and the muscle phenotypic modulator TGF-β is also increased in ischemia, we hypothesized the mechanotransduction and TGF-β signaling pathway play active role in the differentiation of cardiac fibroblasts to myofibroblasts. Here, we show that the mechanosensitve ion channel TRPV4 is required for TGF-β-induced differentiation of cardiac fibroblasts into myofibroblasts. We found that, the TRPV4-specific antagonist, AB159908 significantly inhibited TGFβ-induced differentiation as measured by incorporation of α-SMA in actin stress fibers (p &lt; 0.05). In contrast, AB159908 did not affect the proliferation of cardiac fibroblasts. Importantly, calcium imaging experiments with Fluo-4 revealed that TGF-β treated fibroblasts exhibit enhanced TRPV4-dependent calcium influx compared to untreated controls (3 fold; p&lt; 0.05). Further, we found that TGF-β-induced myofibroblast differentiation is regulated by the variations in ECM elasticity in a TRPV4 dependent manner. Finally, TGF-β induced myofibroblast differentiation is significantly reduced in cardiac fibroblasts from TRPV4 KO mice compared to controls. Taken together these results suggest, for the first time, that a mechanosensitive ion channel, TRPV4 regulates cardiac fibroblast differentiation to myofibroblasts which could be used as a novel therapeutic target for the treatment of ischemia and myocardial infarction.
Abstract 184: Acre ST-Segment Elevation Myocardial Infarction (STEMI) Registry (ASTEMIR): Interval Times Since Symptoms and Reperfusion Success
Authors: Sergio Timerman, Maria Margarita Castro Gonzalez, Sebastiao V Neves, Jose A Ramires, Rejane M S Holanda, Roberto Kalil Filho
Journal: Circulation (2012)

Proposal: STEMI treatment and its impact on outcomes are highly dependent on time since symptoms onset. We aimed to evaluate the time intervals between symptoms onset, emergency unit admission, electrocardiogram (EKG) and treatment or transfer to treatment thrombolytic therapy(TT) capable unit and their relation to reperfusion success in the public health system (SUS) of ACRE, Rio Branco, Brazil. Method: The ASTEMIR(Jan 2010-Dec 2011) is the first Brazilian prospective TT registry to include community-based emergency units and general hospitals patients, with a more reliable record of the AMI care reality. It included consecutive STEMI admitted to 3 general hospitals and 8 community-based emergency units. Results: 189 patients (61±12y, 54% males), with high prevalence of hypertension (71%), diabetes (33%) and previous AMI (13%). On admission, 81% had typical chest pain and 37% Killip class≥II. Half of the patients received TT with tenecteplase (median ambulance--to-needle 104min, IQR 87-207) or door-to-needle 289min, IQR 234-437 reperfusion. The general pain-to-admission time was 155min (76-324) and admission-to-EKG,162min (90-393). Both, pain-to-admission and admission-to-EKG were lower in the reperfusion group (110 vs 205 min,p=0.002, and 155 vs 220min,p=0.001,respectively). Conclusion: Pain-to-admission and admission-to-EKG times are related to reperfusion success. Regardless of this, the interval times observed in Acre, Rio Branco are close to the ideal recommended by the guidelines. Improvements in population awareness for readily identificationof AMI and health professional education for higher suspicion of STEMI could meliorate this reality in Acre.
Abstract 18201: PPAR-δ Augments the Interaction Between Platelets and Late EPCs via EDG-2 Signaling Pathway, Leading to Vascular Regeneration
Authors: Jung-Kyu Han, Joo-Yun Won, Jee-Hoon Kang, Jae-Won Lee, Hyun-Jai Cho, Kyung-Woo Park, Hyun-Jae Kang, Byung-Hee Oh, Young-Bae Park, Hyo-Soo Kim
Journal: Circulation (2011)

BACKGROUND EDG (endothelial differentiation gene)-2 is a membrane receptor for LPA (lysophosphatidic acid) which is the major lysophospholipid growth factor generated by platelet activation. We focused on the role of EDG-2 in late EPCs and its regulation by PPAR (peroxisome proliferator activated receptor)-δ. METHODS &amp; RESULTS We confirmed the expression of EDG-2 in human late EPCs. Interestingly, EDG-2 expression was upregulated by GW501516, a highly selective PPAR-δ agonist treatment. ChIP and promoter assays showed it occurred via direct transcriptional activation. GW501516 or the supernatant of activated platelets which should contain LPA increased the proliferation (BrdU) of late EPCs, and enhanced their provasculogenic functions such as chemotaxis (Transwell), planar migration (scratch wound healing), and tube formation ( in vitro Matrigel). Co-treatment of GW501516 and the supernatant resulted in synergism. The above effects were reversed by GSK0660 (PPAR-δ antagonist) or Ki16425 (EDG-2 blocker) treatment, but not so much by PDGF neutralizing antibody. In vivo Matrigel plug assay, neither late EPCs (10^6/plug) nor activated platelets induced capillary formation. But the combination of them robustly formed capillaries filled with RBCs. GW501516 potentiated their interaction, leading to more capillaries. In a mouse carotid injury model, late EPCs (DiI tagging) showed more homing to injury site 30 minutes after operation by GW501516 treatment. IF staining confirmed their interaction with platelets (CD61). After 14 days, GW501516-treated late EPC group showed more re-endothelization (IHC for CD31) and less neointimal formation. PPAR-δ or EDG-2 siRNA transfection blocked all in vivo effects of GW501516. CONCLUSIONS Platelets and late EPCs play a key role in vascular regeneration via EDG-2 - LPA axis. PPAR-δ augments the interaction through EDG-2 upregulation, suggesting its agonist as a good therapeutic candidate for ischemic vascular disease.
Abstract 8426: Racial Differences in Heart Transplant Wait-List and Early Post-Transplant Mortality in the United States
Authors: Tajinder P Singh, Christopher S Almond, David O Taylor, Dionne Graham
Journal: Circulation (2011)

Background: Racial differences in long-term outcomes after heart transplant (HT) are well known. However, racial differences in outcomes among those listed for a HT in the United States (US) have not been characterized. We sought to assess racial and ethnic differences in risk factors and in risk of wait-list and early post-transplant mortality among patients (pts) listed for a HT in the US in the current era Methods and Results: We identified all pts ≥18 yrs of age listed for a primary HT in the US during July, 2006- June, 2009 in the Organ Procurement and Transplant Network database. Of 7361 pts analyzed, 69% were white, 20% black, 7% Hispanic and 3% were “other’. Black and Hispanic pts were younger than white pts and were more likely to have blood type O (black 48%, Hispanic 53%, white 42%), dilated cardiomyopathy (71%, 56%, 39%, respectively), pulmonary artery wedge pressure &gt;20 mm Hg (55%, 54%, 47%, respectively), listing status 1A or 1B (68%, 63%, 53%, respectively) and public medical insurance (25%, 26%, 10%, respectively) (P&lt;0.001 for all). Overall, 11.5% of white, 12.5% of black and 14.8% of Hispanic pts listed for a HT died on the wait-list or became too sick to transplant. In an analysis adjusted for age, diagnosis, listing status, pulmonary artery wedge pressure, support variables (inotropes, ventilator, mechanical support, implantable cardioverter defibrillator) and renal function, both black (hazard ratio [HR] 1.19, 95% confidence interval [CI] 0.99, 1.43) and Hispanic (HR 1.65, 95% CI 1.25, 2.05) pts were at higher risk of dying on the wait-list or becoming too sick to transplant compared to white pts (P=0.002). These risks remained unchanged after further adjustment for blood type and medical insurance. Compared to white HT recipients, post-transplant in-hospital mortality was higher in black recipients (Odds ratio [OR] 1.47, 95% CI 1.13, 1.91) but was not different in Hispanic recipients (OR 0.87, CI 0.57, 1.32). Conclusions: Black and Hispanic pts listed for a HT in the US appear to be at higher risk of dying on the wait-list or becoming too sick to transplant compared to white pts. Black pts also appear to be at higher risk of early post-transplant mortality. Understanding the mechanisms for these racial differences in outcomes requires further investigation.
Abstract 8407: The T-peak to T-end Interval Independently Predicts Both Ventricular Tachyarrhythmia and Death in Patients with Cardiomyopathy and an Implanted Defibrillator
Authors: Daniel P Morin, Marc N Saad, Omar F Shams, J S Owen, Joel Q Xue, Freddy M Abi-Samra, Sammy Khatib, Onajefe S Nelson-Twakor, Richard V Milani
Journal: Circulation (2011)

Background: The heart rate-corrected T wave peak to T end interval (Tpe c ), an electrocardiographic (ECG) index of dispersion of ventricular repolarization, has been proposed as an indicator for arrhythmic risk. The real-world clinical value of Tpe c for risk stratification is unclear. Methods: We evaluated 327 patients (75% M, LVEF 23±7%) with LVEF &lt;=35% and an ICD. Clinical data and ECGs were analyzed at baseline. Follow up for appropriate ICD therapy and death was conducted via device interrogation and the Social Security Death Index. Results: During device clinic follow-up of 17±12 months, 59 (18%) patients had appropriate ICD therapy, and during mortality follow-up of 30±13 months, 67 (21%) patients died. Tpe c predicted ICD therapy, death, and the combination of appropriate ICD therapy or death (p&lt;0.01 for each endpoint; see Figures stratified by tertiles of Tpe c : T1, T2, T3). On multivariable analysis correcting for other predictors including demographics, clinical data, medication use, and ECG parameters, Tpe c remained predictive of ICD therapy (HR per 10 ms increase: 1.16, p=0.02), all-cause mortality (HR per 10 ms: 1.14, p=0.03), and the combined endpoint of ICD therapy or death (HR per 10 ms: 1.16, p&lt;0.01). Conclusion: In patients with left ventricular systolic dysfunction and an implanted ICD, Tpe c independently predicts both ventricular tachyarrhythmia and overall mortality.
Abstract 18558: Characterization of Cx43-PKP2 Interaction by Direct Stochastic Optical Reconstruction Microscopy
Authors: Esperanza Agullo-Pascual, Dylan Reid, Eli Rothenberg, Mario Delmar
Journal: Circulation (2012)

The cardiac intercalated disc is composed of 3 structures involved in the electrical and mechanical coupling of the cardiomyocytes: gap junctions, desmosomes and adherens junctions. Several studies suggest that these structures interact at the intercalated disc. In particular a crosstalk between the desmosomal and gap junction proteins PKP2 and Cx43 has been demonstrated. To characterize the proximity of these two proteins we used a Duolink assay. With this method, we demonstrated that Cx43 and PKP2 reside in the periphery of the adult cardiac intercalated disc at distances &lt;40 nm. To further investigate this interaction we performed direct stochastic optical reconstruction microscopy (dSTORM) experiments. This new approach is a valuable methodology for studying the cellular architecture at the nanoscale. The dSTORM uses standard fluorescent dyes that are controlled by the laser excitation intensity and the imaging buffer conditions can be induced to switch on and off (“blink”). For these experiments, 2.000 images were recorded in a stack, each of these images showing a different subset of the fluorescent dyes active. The analysis of these images (the localization of each blink) gave a reconstructed super-resolution image with a resolution of 10nm. The images obtained in isolated neonatal cardiomyocytes showed that 43.5% of the Cx43 spots/clusters analysed (n=200 of 5 experiments) are an average of 11.38 nm apart from PKP2 (SE= 1.67), 62% of them being in contact (0nm). In conclusion, these two techniques allow us to visualize the interaction and distribution of Cx43 and PKP2 at the nanoscale in the intercalated disc and suggest that a fraction of PKP2 molecules interact directly with Cx43.
Abstract 18614: Comparison of the New EuroSCORE II with the Original EuroSCORE and the Society of Thoracic Surgeons Risk Score
Authors: Niv Ad, Linda Henry, Sharon Hunt, Sari holmes
Journal: Circulation (2012)

Background: The new EuroSCORE II was developed to improve the prediction risk model of the EuroSCORE I.. In the USA, the Society of Thoracic Surgeons (STS) risk score is more accepted despite being less user friendly and non-applicable to some of the cardiac surgeries. The purpose of this study was to compare the performance of the new EuroSCORE II with the logistic EuroSCORE I and STS mortality predicted risk score . Methods: Prospectively collected data from all cardiac surgery patients at a single center with complete data for the three scores (N=9,966) was used. A subabnalysis for patients with cardiac surgeries not accommodated by the STS risk model was performed for comparison of the EuroSCORE II &amp; I (N=4,738). Correlations were conducted between each score and ROC curves were calculated for operative mortality determining the discriminative ability score. Results: Our center’s observed operative mortality was 2% -the mean predicted mortality for STS was 2.8%, 3.3% for EuroSCORE II and 7.7% for EuroSCORE I. The discriminative ability of the EuroSCORE II for operative mortality by the area under the curve (AUC) was 0.836, for EuroSCORE I (AUC=0.812) and for the STS score (AUC=0.833). The EuroSCORE II was highly correlated with the EuroSCORE I ( r =0.83, p &lt;0.001) and the STS score ( r =0.78, p &lt;0.001). The EuroSCORE II had a higher correlation with the STS score than the EuroSCORE I ( r =0.70, p &lt;0.001). In the subanalyses comparing the EuroSCORE II vs I, the scores were highly correlated ( r =0.74, p &lt;0.001). For operative mortality (observed=4%), the EuroSCORE II had better discriminative ability (expected=5.6%, AUC=0.749) compared to EuroSCORE I (expected=12.4%, AUC=0.687). Conclusions: The new EuroScore II has better operative mortality discrimination compared to the original EuroSCORE, which greatly overestimated the predicted risk of operative mortality. The EuroSCORE II fared well with the STS risk score. Due to the inclusive nature of the EuroSCORE II for multiple procedures, it provides more flexibility than the STS score when dealing with patients undergoing very complex procedures. The EuroSCORE II should be considered when obtaining a risk score for complex cardiac surgical patients.
Abstract 18585: Purification of Cardiomyocytes from Differentiating Human Pluripotent Stem Cells Using Molecular Beacons Targeting mRNA of a Cardiomyocyte-specific Gene
Authors: Kiwon Ban, Brian Wile, Sangsung Kim, Jaemin Byun, Talib Saafir, Mary Wagner, Gang Bao, Young-sup Yoon
Journal: Circulation (2012)

Background: While various methods for generating cardiomyocytes (CMs) from pluripotent stem cells (PSCs) including both embryonic stem cells (ESCs) and recently identified induced pluripotent stem cells (iPSCs) have been reported, all available methods are only able to produce heterogeneous populations of CMs mixed with non-CM cells. Therefore, strategies to enrich pure CMs for scientific and clinical applications are urgently required. In the present study, we developed an entirely novel system in which PSC-derived CMs can be purified by cardiac-specific molecular beacons (MBs). MBs are nano-scale probes that emit a fluorescence signal when hybridized to target mRNAs. We hypothesized that MBs targeted to CM-specific mRNAs can identify CMs and allow isolation of CMs by FACS. Method and Results: Five MBs targeting distinct sites on mRNA of either cardiac troponin T or myosin heavy chain 6 and -7 were designed and characterized in HL-1 CMs, an immortalized mouse CM cell line and several non-CM cell types such as mouse smooth muscle cells and fibroblasts. Among five MBs in flow cytometry analysis, MHC1-MB identified up to 98% of HL-1 CMs but less than 5% of non-CM cell types, indicating that MHC1-MB is specific for identifying CMs. Subsequently, MHC1-MBs delivered into heterogeneous mouse and human PSC differentiation cultures identified 41 to 49% of the MB + cells. Interestingly, the rates of MB + cells were highly correlated with the rate of cTnT/I + cells, supporting their specificity for detecting PSC-derived CMs. Finally, we determined whether cell sorting with MHC1-MBs can enrich CMs from mouse and human PSC differentiating cultures and found that ∼97% of MB-based sorted CMs expressed cTnT/I. Importantly, these MB-based sorted cells continuously maintained their CM characteristics, which were verified by observation of spontaneous beating and significant expression of cardiac specific genes and proteins in qRT-PCR analysis and immunocytochemistry. Furthermore, Ca 2+ transient analysis confirmed that these enriched cells displayed functional CM characteristic. Conclusion: Using cardiac-specific MBs, we were able to obtain highly purified CMs. These purified CMs and this system can be highly useful for cell therapy as well as drug discovery.
Abstract 18583: A Method for Improving the Identification of Heart Failure Patients for Quantitative Clinical Performance Measures using Electronic Health Records
Authors: Sinziana Seicean, Andreea Seicean, Thomas H Marwick
Journal: Circulation (2012)

Background: Electronic Health Records (EHR) are recommended for providing relevant data measures for quantifying and improving health care quality in pts with Heart Failure (HF). However, little is known on the feasibility and reliability of corroborating data fields automatically extracted from EHR to detect the HF population. We sought to improve the definition of pts diagnosed with HF using clinical and revenue functions of EHR. Methods: A standardized approach was developed using Epic's Clarity application to extract and integrate expanded administrative raw data from two sources: “Problem List Diagnosis Files” (PLDF) and “Encounter Diagnosis Administrative Files” (EDAF). HF diagnosis was extracted from the combined data, with each source considered equally valid, by using the ICD-9-CM Diagnosis Code set and methodology recommended by the 2010 Heart Failure Working Group. Results were compared against the “gold standard”, comprised through manual extraction of HF diagnosis by three clinicians, which was further validated by an experienced EHR research data extractor in a sample of 1000 in- and outpatients. Results: 68 HF pts were identified by "gold standard manual extraction", while the administrative files (EDAF) detected only 50 pts; use of both sources detected HF 64 pts. Automated data extraction showed high specificity (0.99) for both methods, sensitivity increased from 0.72 with traditional administrative claims to 0.93 by corroborating EDAF with the PLDF. Conclusions: Corroborating two automated extracted data fields: PLDF and EDAF as equally valid sources was a superior strategy to ensure that patients were not incorrectly excluded from quality measures. The detection of HF using ICD9 codes appeared feasible. Correct definition of the patient population with HF is a critical prerequisite for accurate assessment of all quantitative clinical performance measures.