tbuckley/cabot-search huggingface dataset:
Abstract Mo032: Biofabrication of Small Vascular Graft using Human Amniotic Membrane
Authors: Bo Wang
Journal: Circulation Research (2024)

Vascular diseases encompass a spectrum of pathological conditions affecting blood vessels, including cerebrovascular disease, coronary heart disease, aneurysms, deep vein thrombosis, and peripheral arterial disease. In severe cases, surgical interventions such as bypass grafting or vascular replacement surgeries are necessary to restore blood flow by bypassing obstructed vessels with functional vascular substitutes. Autologous blood vessels harvested from patients are considered the gold standard for vascular surgeries. However, their availability is limited in patients with pre-existing chronic diseases or previous vessel harvest, and the associated morbidities of vessel harvesting and subsequent surgeries further restrict their therapeutic applicability. Synthetic grafts, including polytetrafluoroethylene (e-PTFE), polyethylene terephthalate (PET), and polyurethane (PU), have obtained FDA approval for clinical application and have shown satisfactory outcomes in large vessel surgeries (internal diameter &gt; 6mm). However, clinical trials targeting medium (6-10 mm) to small (&lt; 6mm) vessels often yield unsatisfactory results. This study aims to develop a small vascular graft using human amniotic membrane (HAM) that meets the structural, mechanical, and biological requirements for human vascular reconstructive surgeries. Fresh HAMs were decellularized with 1% Triton X-100 and 0.1% sodium dodecyl sulfate to prepare decellularized HAM (DAM). The DAM was trimmed into a rectangular shape and rolled around a catheter to prepare a tubular-shaped DAM vascular graft. After rolling, the DAM grafts were crosslinked with 1% genipin for 24 hours followed by thorough water washing. The final DAM vascular graft exhibited a multi-layered wall structure and comparable dimensions and mechanical properties to native arteries. The DAM vascular graft was further evaluated in vivo by replacing part of the rat abdominal aorta and part of the carotid artery in pigs. Both small and large animal studies demonstrated vascular patency with no neointimal hyperplasia (NIH), suggesting that the DAM graft holds significant promise as a small tissue-engineered vascular graft for future vascular reconstruction surgeries.
Abstract Tu119: The exocyst trafficking complex mediates fuel transporter membrane delivery in cardiomyocytes.
Authors: Connor Schuller, Herena Ha, Nicole Nakamura, Luke Nelson, Darcy Tokunaga, Emi Lin Luo, Kathryn Schunke, Noemi Polgar
Journal: Circulation Research (2024)

Introduction: To maintain homeostasis, cardiomyocytes (CMs) primarily rely on fatty acid β-oxidation for ATP production facilitated by substrate uptake via fuel transporters. The glucose transporter, GLUT4, and fatty acid translocase, CD36, are directed to the cardiomyocyte sarcolemma in response to insulin signaling and AMP-activated protein kinase (AMPK) signaling. In adverse conditions like acute hypoxia and ischemia, these cells undergo a metabolic shift to favor glycolysis. Previous reports showed that under these conditions, CD36 moved away from the sarcolemma as GLUT4 was delivered to the cell membrane, contributing to a shift from fatty acid oxidation to glycolysis. Investigating CD36 and GLUT4 membrane delivery in cardiomyocytes is key to better understanding cardiac energy metabolism under normal and disease conditions. Prior work in adipocytes, and our own studies in skeletal muscle showed that the exocyst trafficking complex is critical for membrane delivery of GLUT4 and CD36 in response to insulin and AMPK. Our objective was to determine if in cardiomyocytes GLUT4 and CD36 trafficking, and subsequent fuel uptake is dependent on the exocyst. Methods and Results: We demonstrate that the exocyst is recruited to GLUT4 and CD36-vesicles in cultured H9C2 cells in response to stimuli with proximity ligation assays. Using on-cell Western analysis and fuel uptake assays we also show that the exocyst is essential for induced GLUT4 and CD36 cell surface delivery and subsequent energy substrate uptake, as inhibition of the exocyst attenuates stimulated surface translocation of both fuel transporters and subsequent fluorescent fuel analog uptake. Our earlier work revealed that protein levels of exocyst subunits are increased in murine heart tissue following myocardial infarction. To examine the role of the exocyst in fuel uptake under ischemic conditions, we used an in vitro model of simulated ischemia, and found similar alterations in exocyst subunit expression in this model at both mRNA and protein levels. This suggests an increased demand for exocyst activity. Conclusion: Further research will explore how ischemia impacts exocyst-mediated trafficking and if the exocyst contributes to the glycolytic shift under ischemia in cardiomyocytes.
Abstract Mo039: Risk of Structural and Hemodynamic changes in Left Atrium in Patients with Heart Failure undergoing Percutaneous Left Atrial Appendage Occlusion: A Retrospective Analysis
Authors: Bharat Rawlley, Kartik Gupta, Kannu Bansal, Pratyaksh Vaishnav, Rohan Kumar Ochani, Subaina Khalid, Alexander Somerville, Andres Cordova Sanchez, Debanik Chaudhuri
Journal: Circulation Research (2024)

Background: Exclusion of left atrial appendage (LAA) in animals reduces compliance and increases left atrial pressure. We hypothesize that percutaneous left atrial appendage occlusion (LAAO) would lead to structural and hemodynamic changes in left atrium and assess the risk using echocardiographic cut-offs used for evaluating left atrial pressure in heart failure patients. Methods: We queried TriNetx database for adult patients with heart failure undergoing percutaneous LAAO. We excluded those who underwent surgical or alternative percutaneous procedures pertaining to LAA, procedures pertaining to mitral valve (MV), mitral valvular pathologies, mechanical circulatory support placement, pacemaker placement, and those with left bundle branch block. We calculated risk of meeting echocardiographic cut-offs used in evaluation of left atrial pressure; MV maximum E-wave velocity ≥50cm/s, left atrial end systolic volume index (LAESVI) indexed to body surface area ≥34 ml/m2, Tricuspid Regurgitation systolic jet velocity ≥ 2.8 m/s, Pulmonary vein Systole/Diastole ratio ≤ 1, mitral valve lateral annulus E/e' ≥ 13 and Mitral valve E/A ratio ≥2. Those meeting the respective cut-off before LAAO were excluded. All diagnoses, procedures, and echocardiographic parameters were identified using International Classification of Diseases, Current Procedural Terminology, and Logical Observation Identifiers Names and Codes. Results: We identified 4,046 patients with heart failure undergoing percutaneous LAAO. Baseline demographics and diagnosis were; mean (SD) age 75.4 (8.1) years, 37% females, 92% hypertension, 67% ischemic heart disease, 42% diabetes mellitus, 41% chronic kidney disease, and 42% were overweight or obese. Risk of meeting echocardiographic cut-offs used in evaluating left atrial pressure was low with 0.24% (10) patients having LAESVI indexed to body surface area ≥34 ml/m2, Tricuspid Regurgitation systolic jet velocity ≥ 2.8 m/s, Pulmonary vein Systole/Diastole ratio ≤ 1, and Mitral valve E/A ratio ≥ 2. Risk of having MV maximum E-wave velocity ≥50cm/s was 0.58% and no patients had mitral valve lateral annulus E/e' ≥ 13. (Figure 1) Conclusion: Risk of meeting echocardiographic cut-offs used in evaluation of left atrial pressure in patients with heart failure undergoing percutaneous LAAO is low.
Abstract Tu095: Cycloastragenol Alleviates Cardiac Fibrosis through Inhibiting Pyroptosis Activated by NLRP3 Inflammasome
Authors: RONG QI
Journal: Circulation Research (2024)

Cardiac fibrosis is cardiac interstitial remodeling characterized by an enhanced extracellular matrix deposition. Acute sympathetic stress causes cardiac cells to immediately undergo pyroptosis, which induces cardiac inflammation and damage, and ultimately results in cardiac fibrosis. Our previous study has demonstrated the inhibitory effects of cycloastragenol (CAG), an active form of astragaloside IV isolated from Astragalus membranaceus, on isoproterenol (ISO)-induced cardiac fibrosis through blocking the NLRP3 signaling pathway. It is yet unknown how CAG affects pyroptosis of cardiac cells and whether its ability to prevent cardiac fibrosis coincides with this process. In this study, 5 mg/kg ISO was subcutaneously injected into wild-type (WT), NLRP3 knockout (KO), and GSDMD KO mice for 7 days to induce cardiac fibrosis. CAG (125 mg/kg/d) was administrated to the mice intragastrically at the start of the ISO injection. Primary cardiomyocytes and cardiac fibroblasts were isolated from neonatal rat hearts and treated with 10 μM ISO either with or without CAG. The results show that CAG alleviates cardiac fibrosis in WT mice, while lost this efficacy in NLRP3 KO mice. GSDMD KO mice do not develop ISO-induced cardiac fibrosis, indicating the key role of pyroptosis in cardiac fibrosis. Pyroptosis mainly occurs in mouse hearts during the initial stages of ISO induction (1 and 24 hours after ISO injection), and CAG significantly reduces pyroptosis of heart cells in WT mice, while CAG is unable to prevent pyroptosis in NLRP3 KO mouse hearts. The TGF-/Smads signaling pathway is also inhibited by CAG in WT mice but not in NLRP3 KO mice. Additionally, CAG prevents the in vitro pyroptosis of cardiomyocytes induced by ISO directly and cardiac fibroblasts caused by LPS+ATP. These results suggest that the principal mechanism of the anti-cardiac fibrosis effect of CAG mainly depends on its inhibition of pyroptosis mediated by NLRP3 inflammasome.
Abstract Tu121: Investigating Mechanisms Of MCUB Inhibition Of Mitochondrial Calcium Uptake
Authors: Neeraj Rai, Dipayan Chaudhuri
Journal: Circulation Research (2024)

The mitochondrial calcium uniporter mediates Ca 2+ entry into the matrix, and matches energetic supply to demand during cardiac activity. However, many cardiac diseases are characterized by mitochondrial Ca 2+ overload, such as ischemia/reperfusion (I/R) injury. The uniporter channel is typically formed by a tetramer of MCU subunits. These subunits have two transmembrane domains and create a pore lined with negative charges to allow rapid and selective Ca 2+ permeation. Intriguingly, many studies have shown that a close homolog, MCUB can potentially oligomerize with MCU subunits to alter the pore. When the tetramer is made of MCU Ca 2+ transmission is facilitated, but the presence of MCUB inhibits Ca 2+ intake through the channel, suggesting that it is a dominant negative subunit. Moreover, recent studies in animals subject to ischemic cardiovascular injury has revealed endogenous upregulation of the MCUB subunit, proposed as an endogenous mechanism to prevent Ca 2+ overload. Deletion of MCUB enhances activation and uptake when exposed to high Ca 2+ , making MCUB −/− cells prone to mitochondrial Ca 2+ overload and pore opening. Here, we investigate the mechanisms by which MCUB regulates the behavior of the channel, focusing on how MCUB may influence complex composition and regulate its targeting. For this study, we performed structure-function studies of reconstituted MCUB in MCU -/- MCUB -/- double knockout HEK 293T cells. Using modified MCUB constructs and a range of MCU to MCUB transfection ratios, we queried how many MCUB subunits can successfully incorporate into uniporter complex. We subsequently created a range of tetrameric concatemers featuring different ratios of MCU to MCUB, allowing us to observe that increasing amounts of MCUB incorporation lead to greater inhibition of mitochondrial Ca 2+ uptake. Finally, we examined whether replacing portions of MCUB with the corresponding MCU sequence was able to rescue Ca 2+ uptake, finding that these substitutions failed to significantly increase mitochondrial Ca 2+ uptake. Our findings clarify how MCUB incorporation into the uniporter complex leads to dominant-negative inhibition of mitochondrial Ca 2+ uptake.
Abstract Tu077: Targeting β-adrenergic receptor resensitization attenuates cardiac dysfunction
Authors: Yu Sun, Maradumane Mohan, Kate Stenson, Sathyamangla Naga Prasad
Journal: Circulation Research (2024)

β-adrenergic receptor (βAR) is a key regulator of cardiac function. Agonist activation of βAR leads to phosphorylation-mediated desensitization resulting in βAR trafficking to endosomes. Endosomal βARs undergo resensitization through protein phosphatase 2A (PP2A)-mediated dephosphorylation. We have shown that stimulation of βARs activates phosphoinositide 3-kinase γ (PI3Kγ) that phosphorylates endogenous inhibitor of PP2A (I2PP2A) promoting robust binding to PP2A resulting in PP2A inhibition. βAR dysfunction due to desensitization is considered as a classical hallmark of heart failure, while less is known about resensitization. Plasma membrane and endosomal fractions were isolated from non-failing and failing patient samples to determine whether βAR resensitization is altered in human heart failure. Endosomes from heart failure samples showed significant accumulation of phosphorylated β2ARs which was associated with reduced adenylyl cyclase and βAR-associated PP2A activity compared to non-failing showing that resensitization is inhibited in human heart failure. Since PP2A activity is inhibited by robust binding of I2PP2A to PP2A, we hypothesized that disrupting I2PP2A interaction with PP2A would unlock PP2A inhibition normalizing βAR resensitization. In silico modeling and biochemical studies mapped the PP2A interaction with I2PP2A to the C-terminal region of PP2A (PP2Act). Agonist isoproterenol (ISO) treatment of cells expressing PP2Act showed significant reduction in β2AR phosphorylation along with increased cAMP generation and normalized PP2A activity showing preserved βAR resensitization. While expression of PP2A mutant with deletion in the PP2Act (ΔPP2Act) did not preserve βAR resensitization. Challenging mice with cardiomyocyte-specific expression of PP2Act to ISO showed preserved cardiac function providing insights that targeting resensitization could potentially be a novel therapeutic strategy. Key words: Resensitization, I2PP2A, PP2A, Cardiac hypertrophy
Abstract Tu073: Mst1 induces cardiac dysfunction through the activation of PERK
Authors: Risa Mukai, Soichiro Usui, Peiyong Zhai, Yasuki Nakada, Junichi Sadoshima
Journal: Circulation Research (2024)

Introduction: Mammalian sterile 20-like kinase 1 (Mst1), a major component of the Hippo pathway, promotes cell death and differentiation, but inhibits cell growth, thereby contributing to the development of heart failure. We discovered that Mst1 activates protein kinase RNA-like endoplasmic reticulum kinase (PERK), a kinase responsible for the integrated stress response (ISR). Aim: We investigated whether Mst1-induced PERK activation is involved in the development of heart failure. Methods and results: Mst1 induces phosphorylation of the cytoplasmic domain of PERK, thereby activating it. We generated knock-in mice expressing a PERK mutant, which is not phosphorylated by Mst1, (PERK-KI). Although PERK was activated by tunicamycin, an ER stress inducer, it was not activated by transverse aortic constriction (TAC) in PERK-KI mice in vivo . To investigate the effect of Mst1-induced PERK phosphorylation on cardiac function, cardiac-specific Mst1 transgenic mice (Tg-Mst1) mice were crossed with heterozygous (h) PERK-KI mice (Tg-Mst1-hPERK-KI). The level of phosphorylation of eIF2α, a PERK substrate, was decreased in Tg-Mst1-hPERK-KI mice compared to in Tg-Mst1 mice (0.45-fold, p&lt;0.05). Left ventricular ejection fraction (LVEF) was maintained in Tg-Mst1-hPERK-KI mice compared to in Tg-Mst1 mice (46% vs Tg-Mst1 34%, p&lt;0.05), which was accompanied by reduced fibrosis (3.5% vs Tg-Mst1-hPERK-KI 2.2%, p&lt;0.05) in the heart. We investigated the role of the Mst1-PERK pathway during TAC. Mst1 in wild-type (WT) mice was activated by TAC for 4 weeks (2.4-fold). LVEF was preserved in hPERK-KI mice compared to in WT mice (67% vs WT 46%, p&lt;0.05) after 8 weeks of TAC. Increases in lung weight/tibia length were attenuated in hPERK-KI mice than in WT mice (9.6 vs WT 11.5, p&lt;0.05). Conclusion: Mst1 triggers ISR through phosphorylation of PERK, which in turn plays a significant role in mediating heart failure during pressure overload.
Abstract Mo031: Tissue deficiency and altered eicosanoids levels in rodent and human heart failure.
Authors: Petr Kala, Jan Mikula, Tomas Hnat, Matus Miklovic, Petra Skaroupkova, Zdenka Vanourkova, Karel Kotaska, Petr Ostadal, Vojtech Melenovsky, Ludek Cervenka
Journal: Circulation Research (2024)

Introduction: The role of eicosanoids, especially epoxyeicosatrienoic acids (EETs), metabolites of arachidonic acid with cardio-renal activity, in heart failure (HF) remains unclear. Hypothesis: Altered eicosanoids turnover, both in rodent and human heart failure, is a part of the pathophysiology of HF and contributes to poor prognosis. Methods: We measured active EETs and their biologically inactive metabolites, dihydroxyeicosatrienoic acids (DHETs) in the left ventricle (LV) and renal tissue obtained from a rodent heart failure model induced by aortocaval fistula (ACF). We measured protein expression of CYP2C23 and CYP2J3 in the kidney cortex and LV tissue by Western blot analysis to evaluate EETs production and mRNA expression of soluble epoxide hydrolase (sEH), the enzyme responsible for the degradation of EETs to DHETs. In the translational part, firstly, we enrolled 50 patients with HF to measure plasma 14,15-epoxyeicosatrienoic acid (14,15-EET) and 14,15-dihydroxyicosatrienoic acid (14,15-DHET) levels using commercial ELISA kits and compared them with 25 age- and sex-matched controls. Secondly, 11 consecutive patients with HFrEF indicated to cardiac resynchronization therapy (CRT) were enrolled to measure plasmatic 14,15-EET and 14,15-DHET levels in venous, arterial, and coronary sinus (CS) blood samples and correlate them with N-terminal pro-B-type natriuretic peptide (NT-proBNP) from the same compartments. Results: ACF rats exhibited tissue deficiency of EETs in the LV and kidney compared to controls, probably mainly caused by increased EETs degradation by sEH (unchanged expressions of CYP2C23 and CYP2J3, increased mRNA of sEH and EETs/DHETs ratio). In humans, both of the measured eicosanoids were significantly higher in the HF group: 14,15-EET (91.3 ±25.7 vs. 64.95 ±35.4 ng/ml) and 14,15-DHET (10.58 ±2.06 vs. 9.07 ±1.60 ng/ml), p for both &lt; 0.001. HF patients with 14,15-EET levels less than 60 ng/ml had worse short term mortality compared to those above. In CS, NT-proBNP levels negatively correlated with plasmatic 14,15-EET levels (r = -0.63, p = 0.03) and positively with the DHET/EET ratio (r = 0.73, p = 0.02). Plasmatic 14,15-EET nor 14,15-DHET levels in measured compartments did not differ statistically (p = 0.21, p = 0,64, respectively). In individual patients, the levels of both eicosanoids correlated across all compartments. Conclusions: Tissue deficiency of active eicosanoids and their altered turnover may play an important role in HF pathophysiology.
Abstract Tu015: Angiopoietin-like 4 Stabilizes Atherosclerotic Plaques by Modulating the Phenotypic Transition of Endothelial Cells and Vascular Smooth Muscle Cells
Authors: Dong-Im Cho, Hyang Cho, Meeyoung Cho, Bogyeong Kang, YongSook Kim, Youngkeun Ahn
Journal: Circulation Research (2024)

Atherosclerosis, the leading cause of death, is a vascular disease of chronic inflammation. We recently showed that angiopoietin-like 4 (ANGPTL4) promotes cardiac repair by suppressing pathological inflammation. Given the fundamental contribution of inflammation to atherosclerosis, we assessed the role of ANGPTL4 in the development of atherosclerosis and determined whether ANGPTL4 regulates atherosclerotic plaque stability. We injected ANGPTL4 protein twice a week into atherosclerotic Apoe-/- mice and analyzed the atherosclerotic lesion size, endothelial dysfunction, inflammation, and plaque stability. In atherosclerotic mice, ANGPTL4 reduced the atherosclerotic plaque size, endothelial dysfunction, and vascular inflammation. Furthermore, ANGPTL4 was associated with maintenance of vascular integrity and attenuated endothelial-to-mesenchymal transition (EndMT) in both HUVEC and atherosclerotic plaque of Apoe-/- mice. In the atherosclerotic lesions and fibrous caps, the number of α-SMA(+), SM22α(+), and SM-MHC(+) cells was higher, while the number of CD68(+) and Mac2(+) cells was lower in the ANGPTL4 group. Most importantly, the fibrous cap was significantly thicker in the ANGPTL4 group than in the PBS group. Smooth muscle cells (SMCs) isolated from atherosclerotic aortas showed significantly increased expression of CD68 and Krüppel-like factor 4 (KLF4), a modulator of the vascular SMC phenotype, along with downregulation of α-SMA, and these changes were attenuated by ANGPTL4 treatment. Furthermore, ANGPTL4 reduced TNFa-induced NADPH oxidase 1 (NOX1), a major source of reactive oxygen species, resulting in attenuation of KLF4-mediated SMC phenotypic changes. Our results reveal that ANGPTL4 treatment inhibits atherogenesis and suggest that targeting vascular stability and inflammation may serve as a novel therapeutic strategy to prevent and treat atherosclerosis. Even more importantly, ANGPTL4 treatment inhibited the phenotypic changes of SMCs into macrophage-like cells by downregulating NOX1 activation of KLF4, leading to the formation of more stable plaques.
Abstract Mo108: Sex-specific Impact of Glutathione Precursor-supplemented Diet on the Aging Mouse Heart
Authors: Aude Angelini, Grecia Garcia Marquez, Anna Malovannaya, Marta Fiorotto, Alexander Salzman, Antrix Jain, JoAnn Trial, George Taffet, Katarzyna Cieslik
Journal: Circulation Research (2024)

Common features of the aging heart include dysregulated metabolism, inflammation, and fibrosis, which can all contribute to diastolic dysfunction. Imbalanced oxidative stress can exacerbate each of these conditions, worsening the age-related cardiac defects. Therefore, we hypothesized that increasing natural antioxidant defenses (glutathione) may favor a healthier cardiac aging phenotype. Twenty-one month-old mice were fed for 12 weeks with a diet supplemented in two glutathione precursors, Glycine and N-Acetyl Cysteine (GlyNAC) or with a control diet. Heart function was measured noninvasively and longitudinally at baseline and then every 6 weeks. We found that GlyNAC reduced the age-associated increase in left atrial volume in old male, but not in old female mice ( 12% ± 3% in GlyNAC vs 20% ± 2% in control males (*); 11% ± 3% in GlyNAC vs 16% ± 3% in control females; * P=0.03). It also improved exercise performance in males. Subsequent unbiased cardiac proteome analysis identified that GlyNAC modestly changed global protein expression in males and pointed to the significant changes in two pathways: mitochondria-metabolism and extracellular matrix. Further analysis performed on mitochondrial extracts determined that GlyNAC diet led to an increase in Ndufb8, a subunit of the mitochondrial respiratory chain complex (1.76±0.3 in GlyNAC males vs 0.7±0.1 in control males, P=0.02). In the GlyNAC old male mitochondria, we found an improved catalytic activity for CPT1b (7.51±0.79 vs 3.74±0.32 in control males; P=0.002) and an increased CrAT activity (1.99±0.23 vs 1.06±0.08 in control males; P=0.005). Both enzymes are involved in fatty acid metabolism. Hearts from GlyNAC-fed old males exhibited enrichment in Fmod, a protein that can inhibit collagen fibril formation (1.08±0.03 vs 0.89±0.05, P=0.01), possibly reducing extracellular matrix stiffness. In females, the expression or enzymatic activities of these proteins were not affected by the GlyNAC-supplemented diet. In summary, our study supports the concept that aged male and female hearts exhibit basic phenotypical differences that may affect the response to interventions. These observations may have direct relevance in cardiac gerontology.