275 results on '"Fang, Qizhi"'
Search Results
252. A Non-interleaving Denotational Semantics of Value Passing CCS with Action Refinement
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Zheng, Guang, Li, Shaorong, Wu, Jinzhao, Li, Lian, Hutchison, David, editor, Kanade, Takeo, editor, Kittler, Josef, editor, Kleinberg, Jon M., editor, Mattern, Friedemann, editor, Mitchell, John C., editor, Naor, Moni, editor, Nierstrasz, Oscar, editor, Pandu Rangan, C., editor, Steffen, Bernhard, editor, Sudan, Madhu, editor, Terzopoulos, Demetri, editor, Tygar, Doug, editor, Vardi, Moshe Y., editor, Weikum, Gerhard, editor, Preparata, Franco P., editor, and Fang, Qizhi, editor
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- 2007
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253. On the Complexity of Approximation Streaming Algorithms for the k-Center Problem
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Abdelguerfi, Mahdi, Chen, Zhixiang, Fu, Bin, Hutchison, David, editor, Kanade, Takeo, editor, Kittler, Josef, editor, Kleinberg, Jon M., editor, Mattern, Friedemann, editor, Mitchell, John C., editor, Naor, Moni, editor, Nierstrasz, Oscar, editor, Pandu Rangan, C., editor, Steffen, Bernhard, editor, Sudan, Madhu, editor, Terzopoulos, Demetri, editor, Tygar, Doug, editor, Vardi, Moshe Y., editor, Weikum, Gerhard, editor, Preparata, Franco P., editor, and Fang, Qizhi, editor
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- 2007
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254. Maximizing the Number of Independent Labels in the Plane
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Yu, Kuen-Lin, Liao, Chung-Shou, Lee, D. T., Hutchison, David, editor, Kanade, Takeo, editor, Kittler, Josef, editor, Kleinberg, Jon M., editor, Mattern, Friedemann, editor, Mitchell, John C., editor, Naor, Moni, editor, Nierstrasz, Oscar, editor, Pandu Rangan, C., editor, Steffen, Bernhard, editor, Sudan, Madhu, editor, Terzopoulos, Demetri, editor, Tygar, Doug, editor, Vardi, Moshe Y., editor, Weikum, Gerhard, editor, Preparata, Franco P., editor, and Fang, Qizhi, editor
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- 2007
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255. The On-Line Rental Problem with Risk and Probabilistic Forecast
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Dong, Yucheng, Xu, Yinfeng, Xu, Weijun, Hutchison, David, editor, Kanade, Takeo, editor, Kittler, Josef, editor, Kleinberg, Jon M., editor, Mattern, Friedemann, editor, Mitchell, John C., editor, Naor, Moni, editor, Nierstrasz, Oscar, editor, Pandu Rangan, C., editor, Steffen, Bernhard, editor, Sudan, Madhu, editor, Terzopoulos, Demetri, editor, Tygar, Doug, editor, Vardi, Moshe Y., editor, Weikum, Gerhard, editor, Preparata, Franco P., editor, and Fang, Qizhi, editor
- Published
- 2007
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256. On Coordination Among Multiple Auctions
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Liu, Peter Chuntao, Sun, Aries Wei, Hutchison, David, editor, Kanade, Takeo, editor, Kittler, Josef, editor, Kleinberg, Jon M., editor, Mattern, Friedemann, editor, Mitchell, John C., editor, Naor, Moni, editor, Nierstrasz, Oscar, editor, Pandu Rangan, C., editor, Steffen, Bernhard, editor, Sudan, Madhu, editor, Terzopoulos, Demetri, editor, Tygar, Doug, editor, Vardi, Moshe Y., editor, Weikum, Gerhard, editor, Preparata, Franco P., editor, and Fang, Qizhi, editor
- Published
- 2007
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257. On the Fractional Chromatic Number of Monotone Self-dual Boolean Functions
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Gaur, Daya Ram, Makino, Kazuhisa, Hutchison, David, editor, Kanade, Takeo, editor, Kittler, Josef, editor, Kleinberg, Jon M., editor, Mattern, Friedemann, editor, Mitchell, John C., editor, Naor, Moni, editor, Nierstrasz, Oscar, editor, Pandu Rangan, C., editor, Steffen, Bernhard, editor, Sudan, Madhu, editor, Terzopoulos, Demetri, editor, Tygar, Doug, editor, Vardi, Moshe Y., editor, Weikum, Gerhard, editor, Preparata, Franco P., editor, and Fang, Qizhi, editor
- Published
- 2007
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258. Left atrial mass: relationship between gross anatomy and quantitative echocardiography.
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Flink, Laura, Parwani, Purvi, Ursell, Philip C., Bibby, Dwight, Fang, Qizhi, and Schiller, Nelson B.
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AUTOPSY , *PEARSON correlation (Statistics) , *ANATOMY , *MASS measurement - Abstract
• Left atrial mass has not been defined. • Normal left atrial mass using anatomic specimens was defined. • A simple echocardiographic measurement correlated well with anatomic measurement. Left atrial (LA) enlargement is associated with increased risk of adverse cardiovascular outcomes. Unlike the left ventricular mass, LA mass has not been described. We sought to define the anatomic mass of the LA using anatomic specimens from autopsy. We hypothesized that LA mass could be estimated by echocardiography. Using anatomic specimens of 22 subjects who died and underwent post mortem examination as well as echocardiogram, we defined normal LA mass by weighing anatomic specimens of those with normal LA volume on echocardiogram. Using 17 subjects with normal LA volume on echocardiogram, we found their LA mass on anatomic specimens to be 25.5 ± 6.3 grams (14.4 ± 3.2 g/m2). We developed an echocardiographic measure of LA mass and validated this measurement with paired LA anatomic specimens. We found the normal LA mass on echocardiogram to be 25.4 ± 6.3 g (14.4 ± 2.8 g/m2) which correlated well with anatomic specimens (β = 0.99; Confidence interval CI 0.6–1.4, P <.0001; Pearson correlation coefficient r = 0.83). Furthermore, we defined the normal LA volume to mass ratio as 1.38 ± 0.45. LA mass is an additional parameter with which may contribute to the study of LA morphology. [ABSTRACT FROM AUTHOR]
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- 2020
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259. A Feasibility Study of [ 18 F]F-AraG Positron Emission Tomography (PET) for Cardiac Imaging-Myocardial Viability in Ischemia-Reperfusion Injury Model.
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Shrestha UM, Chae HD, Fang Q, Lee RJ, Packiasamy J, Huynh L, Blecha J, Huynh TL, VanBrocklin HF, Levi J, and Seo Y
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- Animals, Mice, Inbred C57BL, Male, Rats, Mice, Myocardial Infarction diagnostic imaging, Myocardial Infarction pathology, Myocardial Reperfusion Injury diagnostic imaging, Myocardial Reperfusion Injury pathology, Homeodomain Proteins, Positron-Emission Tomography methods, Myocardium pathology, Myocardium metabolism, Disease Models, Animal, Feasibility Studies, Mice, Knockout
- Abstract
Purpose: Myocardial infarction (MI) with subsequent inflammation is one of the most common heart conditions leading to progressive tissue damage. A reliable imaging marker to assess tissue viability after MI would help determine the risks and benefits of any intervention. In this study, we investigate whether a new mitochondria-targeted imaging agent,
18 F-labeled 2'-deoxy-2'-18 F-fluoro-9-β-d-arabinofuranosylguanine ([18 F]F-AraG), a positron emission tomography (PET) agent developed for imaging activated T cells, is suitable for cardiac imaging and to test the myocardial viability after MI., Procedure: To test whether the myocardial [18 F]-F-AraG signal is coming from cardiomyocytes or immune infiltrates, we compared cardiac signal in wild-type (WT) mice with that of T cell deficient Rag1 knockout (Rag1 KO) mice. We assessed the effect of dietary nucleotides on myocardial [18 F]F-AraG uptake in normal heart by comparing [18 F]F-AraG signals between mice fed with purified diet and those fed with purified diet supplemented with nucleotides. The myocardial viability was investigated in rodent model by imaging rat with [18 F]F-AraG and 2-deoxy-2[18 F]fluoro-D-glucose ([18 F]FDG) before and after MI. All PET signals were quantified in terms of the percent injected dose per cc (%ID/cc). We also explored [18 F]FDG signal variability and potential T cell infiltration into fibrotic area in the affected myocardium with H&E analysis., Results: The difference in %ID/cc for Rag1 KO and WT mice was not significant (p = ns) indicating that the [18 F]F-AraG signal in the myocardium was primarily coming from cardiomyocytes. No difference in myocardial uptake was observed between [18 F]F-AraG signals in mice fed with purified diet and with purified diet supplemented with nucleotides (p = ns). The [18 F]FDG signals showed wider variability at different time points. Noticeable [18 F]F-AraG signals were observed in the affected MI regions. There were T cells in the fibrotic area in the H&E analysis, but they did not constitute the predominant infiltrates., Conclusions: Our preliminary preclinical data show that [18 F]F-AraG accumulates in cardiomyocytes indicating that it may be suitable for cardiac imaging and to evaluate the myocardial viability after MI., (© 2024. The Author(s), under exclusive licence to World Molecular Imaging Society.)- Published
- 2024
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260. Primary Atriopathy in Mitral Valve Prolapse: Echocardiographic Evidence and Clinical Implications.
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Tastet L, Lim LJ, Bibby D, Hu G, Cristin L, Rich AH, Jhawar R, Fang Q, Arya F, and Delling FN
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- Humans, Female, Male, Aged, Middle Aged, Heart Atria diagnostic imaging, Heart Atria physiopathology, Atrial Fibrillation physiopathology, Atrial Fibrillation complications, Risk Factors, Severity of Illness Index, Retrospective Studies, Mitral Valve diagnostic imaging, Mitral Valve physiopathology, Echocardiography methods, Mitral Valve Insufficiency physiopathology, Mitral Valve Insufficiency diagnostic imaging, Predictive Value of Tests, Mitral Valve Prolapse physiopathology, Mitral Valve Prolapse complications, Mitral Valve Prolapse diagnostic imaging, Atrial Function, Left, Atrial Remodeling
- Abstract
Background: Prominent multi-scallop systolic leaflet displacement toward the left atrium (atrialization) is typically observed in bileaflet mitral valve prolapse (MVP) with mitral annular disjunction. We hypothesized that mitral leaflet atrialization is associated with an underlying left atrial (LA) myopathy characterized by progressive structural and functional abnormalities, irrespective of mitral regurgitation (MR) severity., Methods: We identified 334 consecutive patients with MVP, no prior atrial fibrillation, and comprehensive clinical and echocardiographic data. LA function was assessed by LA reservoir strain, LA function index, and LA emptying fraction. We also classified the stage of LA remodeling based on LA enlargement and LA reservoir strain (stage 1: no remodeling; stage 2: mild remodeling; stage 3: moderate remodeling; and stage 4: severe remodeling). The primary end point was the composite risk of sudden arrhythmic death, heart failure hospitalization, or the new onset of atrial fibrillation., Results: Bileaflet MVP with no or mild MR had a lower LA reservoir strain ( P =0.04) and LA function index ( P <0.001) compared with other MVP subtypes. In multivariable linear regression adjusted for cardiovascular risk factors and MR ≥moderate, bileaflet MVP remained significantly associated with lower LA function parameters (all P <0.05). There was a significant increase in the risk of events as the LA reservoir strain and LA remodeling stage increased ( P <0.001). In multivariable analysis, stage 4 of LA remodeling remained significantly associated with a higher risk of events compared with stage 1 (hazard ratio, 6.09 [95% CI, 1.69-21.9]; P =0.006)., Conclusions: In a large MVP registry, bileaflet involvement is associated with reduced LA function regardless of MR severity, suggesting a primary atriopathy in this MVP subtype. Abnormal LA function, particularly when assessed through a multiparametric approach, is linked to a higher risk of cardiovascular events and may improve risk stratification in MVP, even in those without significant MR., Competing Interests: Disclosures None.
- Published
- 2024
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261. A feasibility study of [18F]F-AraG positron emission tomography (PET) for cardiac imaging - myocardial viability in ischemia-reperfusion injury model.
- Author
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Shrestha U, Chae HD, Fang Q, Lee RJ, Packiasamy J, Huynh L, Blecha J, Huynh TL, VanBrocklin HF, Levi J, and Seo Y
- Abstract
Purpose: Myocardial infarction (MI) with subsequent inflammation is one of the most common heart conditions leading to progressive tissue damage. A reliable imaging marker to assess tissue viability after MI would help determine the risks and benefits of any intervention. In this study, we investigate whether a new mitochondria-targeted imaging agent,
18 F-labeled 2'-deoxy-2'-18 F-fluoro-9-β-d-arabinofuranosylguanine ([18 F]F-AraG), a positron emission tomography (PET) agent developed for imaging activated T cells, is suitable for cardiac imaging and to test the myocardial viability after MI., Procedure: To test whether the myocardial [18 F]-F-AraG signal is coming from cardiomyocytes or immune infiltrates, we compared cardiac signal in wild-type (WT) mice with that of T cell deficient Rag1 knockout ( Rag1 KO) mice. We assessed the effect of dietary nucleotides on myocardial [18 F]F-AraG uptake in normal heart by comparing [18 F]F-AraG signals between mice fed with purified diet and those fed with purified diet supplemented with nucleotides. The myocardial viability was investigated in rodent model by imaging rat with [18 F]F-AraG and 2-deoxy-2[18 F]fluoro-D-glucose ([18 F]FDG) before and after MI. All PET signals were quantified in terms of the percent injected dose per cc (%ID/cc). We also explored [18 F]FDG signal variability and potential T cell infiltration into fibrotic area in the affected myocardium with H&E analysis., Results: The difference in %ID/cc for Rag1 KO and WT mice was not significant ( p = ns) indicating that the [18 F]F-AraG signal in the myocardium was primarily coming from cardiomyocytes. No difference in myocardial uptake was observed between [18 F]F-AraG signals in mice fed with purified diet and with purified diet supplemented with nucleotides ( p = ns). The [18 F]FDG signals showed wider variability at different time points. Noticeable [18 F]F-AraG signals were observed in the affected MI regions. There were T cells in the fibrotic area in the H&E analysis, but they did not constitute the predominant infiltrates., Conclusions: Our preliminary preclinical data show that [18 F]F-AraG accumulates in cardiomyocytes indicating that it may be suitable for cardiac imaging and to evaluate the myocardial viability after MI., Competing Interests: Declarations Conflicts of Interest JL and HC are employed by CellSight Technologies, Inc., which is developing [18F]F-AraG for commercial use. JL holds patents related to [18F]F-AraG.- Published
- 2024
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262. Local decorin delivery via hyaluronic acid microrods improves cardiac performance, ventricular remodeling after myocardial infarction.
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Mohindra P, Zhong JX, Fang Q, Cuylear DL, Huynh C, Qiu H, Gao D, Kharbikar BN, Huang X, Springer ML, Lee RJ, and Desai TA
- Abstract
Heart failure (HF) remains a global public health burden and often results following myocardial infarction (MI). Following injury, cardiac fibrosis forms in the myocardium which greatly hinders cellular function, survival, and recruitment, thus severely limits tissue regeneration. Here, we leverage biophysical microstructural cues made of hyaluronic acid (HA) loaded with the anti-fibrotic proteoglycan decorin to more robustly attenuate cardiac fibrosis after acute myocardial injury. Microrods showed decorin incorporation throughout the entirety of the hydrogel structures and exhibited first-order release kinetics in vitro. Intramyocardial injections of saline (n = 5), microrods (n = 7), decorin microrods (n = 10), and free decorin (n = 4) were performed in male rat models of ischemia-reperfusion MI to evaluate therapeutic effects on cardiac remodeling and function. Echocardiographic analysis demonstrated that rats treated with decorin microrods (5.21% ± 4.29%) exhibited significantly increased change in ejection fraction (EF) at 8 weeks post-MI compared to rats treated with saline (-4.18% ± 2.78%, p < 0.001) and free decorin (-3.42% ± 1.86%, p < 0.01). Trends in reduced end diastolic volume were also identified in decorin microrod-treated groups compared to those treated with saline, microrods, and free decorin, indicating favorable ventricular remodeling. Quantitative analysis of histology and immunofluorescence staining showed that treatment with decorin microrods reduced cardiac fibrosis (p < 0.05) and cardiomyocyte hypertrophy (p < 0.05) at 8 weeks post-MI compared to saline control. Together, this work aims to contribute important knowledge to guide rationally designed biomaterial development that may be used to successfully treat cardiovascular diseases., (© 2023. Springer Nature Limited.)
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- 2023
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263. Stroke in mitral valve prolapse: risk factors and left atrial function in cryptogenic versus non-cryptogenic ischemic subtypes.
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Calicchio F, Lim LJ, Cross D, Bibby D, Fang Q, Meisel K, Schiller NB, and Delling FN
- Abstract
Background and Purpose: Mitral valve prolapse (MVP) has been associated with an increased risk of ischemic stroke. Older age, thicker mitral leaflets, and significant mitral regurgitation (MR) leading to atrial fibrillation have been traditionally considered risk factors for ischemic stroke in MVP. However, specific risk factors for MVP-stroke subtypes are not well defined. The aim of this study is to evaluate clinical and echocardiographic parameters, including left atrial (LA) function, in MVP with cryptogenic (C) vs. non-cryptogenic (NC) stroke., Methods: In this case-control matched study, MVPs were identified in consecutive echocardiograms obtained after a stroke from January 2013 to December2016 at the University of California, San Francisco. MVP was defined as leaflet displacement ≥2 mm in the parasternal long-axis view at end-systole. Age/gender matched MVPs without stroke and healthy controls without MVP were also identified. We analyzed LA end-systolic/diastolic volume index, emptying fraction (LAEF), function index (LAFI), and global longitudinal strain in all MVPs and controls. We also measured left ventricular (LV) volume indexes, mass index, ejection fraction (EF), degree of MR and leaflet thickness., Results: We identified a total of 30 MVPs (age 70 ± 12, 50% females) with stroke (11 with C- and 19 with NC-stroke), 20 age/gender matched MVPs without a stroke and 16 controls. MVPs without stroke had lower BMI, less hypertension but more MR (≥moderate in 45% vs. 17%), more abnormal LA function (lower LAEF, LAFI) and larger LV volumes/mass (all p < 0.05) when compared to MVPs with stroke. Leaflet thickness was overall mild (<3 mm) and similar in the 2 groups. Within the MVP stroke group, NC-stroke had higher BMI, more hypertension and more atrial fibrillation compared to C-stroke. In the variables tested, patients with C-stroke did not differ from controls., Conclusions: MVP-related MR may be protective against stroke despite abnormal LA function. Risk of NC-stroke in MVP is related to common stroke risk factors rather than mitral valve leaflet thickness. The etiology of C-stroke in MVP warrants further studies., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Calicchio, Lim, Cross, Bibby, Fang, Meisel, Schiller and Delling.)
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- 2023
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264. Local delivery of decorin via hyaluronic acid microrods improves cardiac performance and ventricular remodeling after myocardial infarction.
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Desai T, Mohindra P, Zhong J, Fang Q, Huynh C, Cuylear D, Qiu H, Gao D, Kharbikar B, Huang X, Springer M, and Lee R
- Abstract
Heart failure (HF) is a global public health burden and associated with significant morbidity and mortality. HF can result as a complication following myocardial infarction (MI), with cardiac fibrosis forming in the myocardium as a response to injury. The dense, avascular scar tissue that develops in the myocardium after injury following MI creates an inhospitable microenvironment that hinders cellular function, survival, and recruitment, thus severely limiting tissue regeneration. We have previously demonstrated the ability of hyaluronic acid (HA) polymer microrods to modulate fibroblast phenotype using discrete biophysical cues and to improve cardiac outcomes after implantation in rodent models of ischemia-reperfusion MI injury. Here, we developed a dual-pronged biochemical and biophysical therapeutic strategy leveraging bioactive microrods to more robustly attenuate cardiac fibrosis after acute myocardial injury. Incorporation of the anti-fibrotic proteoglycan decorin within microrods led to sustained release of decorin over one month in vitro and after implantation, resulted in marked improvement in cardiac function and ventricular remodeling, along with decreased fibrosis and cardiomyocyte hypertrophy. Together, this body of work aims to contribute important knowledge to help develop rationally designed engineered biomaterials that may be used to successfully treat cardiovascular diseases., Competing Interests: Conflict of interest: The authors have no conflicts of interest to declare.
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- 2023
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265. Association of Systemic Vascular Resistance Analog and Cardiovascular Outcomes: The Heart and Soul Study.
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Lu DY, Fang Q, Bibby D, Arora B, and Schiller NB
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- Aged, Female, Heart Ventricles, Humans, Male, Middle Aged, Prognosis, Vascular Resistance, Coronary Artery Disease, Heart Failure
- Abstract
Background Systemic vascular resistance (SVR) is an integral component of the hemodynamic profile. Previous studies have demonstrated a close correlation between an estimated SVR analog (eSVR) based on echocardiographic methods and SVR by direct hemodynamic measurement. However, the prognostic impact of eSVR remains unestablished. Methods and Results Study participants with established coronary artery disease from the Heart and Soul Study formed this study cohort. We defined Doppler-derived eSVR as the ratio of systolic blood pressure to left ventricular outflow tract velocity time integral. Study participants were separated based on baseline eSVR tertile: <5.6, 5.6 to <6.9, and ≧6.9. An elevated eSVR was defined as an eSVR in the third tertile (≧6.9). Follow-up eSVR was calculated at the fifth year of checkup. Cardiovascular outcomes included heart failure, major cardiovascular events, and all-cause death. Among the 984 participants (67±11 years old, 82% men), subjects with the highest baseline eSVR tertile were the oldest, with the highest systolic blood pressure and lowest left ventricular outflow tract velocity time integral. A higher eSVR was associated with increased risk of heart failure, major cardiovascular events, and death. The hazard ratio for major cardiovascular events was 1.38 (95% CI, 1.02-1.86, P =0.03) for subjects with the highest eSVR tertile compared with the lowest. In addition, those with a persistently elevated eSVR during follow-up had the most adverse outcomes. Conclusions An elevated eSVR, derived by the ratio of systolic blood pressure and left ventricular outflow tract velocity time integral, was more closely correlated with cardiovascular events than systolic blood pressure alone. Repeatedly elevated eSVR was associated with more adverse outcomes.
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- 2022
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266. Exercise physiology of the left atrium: quantity and timing of contribution to cardiac output.
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Bhatt A, Flink L, Lu DY, Fang Q, Bibby D, and Schiller NB
- Subjects
- Adult, Blood Pressure, Female, Heart Rate, Humans, Male, Middle Aged, Atrial Function, Exercise, Stroke Volume
- Abstract
Although the phases of left atrial (LA) function at rest have been studied, the physiological response of the LA to exercise is undefined. This study defines the exercise behavior of the normal left atrium by quantitating its volumetric response to graded effort. Healthy subjects ( n = 131) were enrolled from the Health eHeart cohort. Echocardiograms were obtained at baseline and during ramped supine bicycle exercise. Left ventricular volume index, stroke volume index (LVSVI), left atrial end-systolic volume index (LAESVI), left atrial end-diastolic volume index (LAEDVI), and left atrial emptying fraction (LAEF), reservoir fraction, and conduit fraction were analyzed. The LVSVI increased with low exercise but did not increase further with peak exercise; cardiac output increased through the agency of heart rate. The LAESVI and LAEDVI decreased and the LAEF increased with exercise. As a result, the LA reservoir volume index was static throughout exercise. The reservoir fraction decreased from 46% at rest to 40% with low exercise ( P < 0.001) in association with increased LVSVI and remained similar at peak exercise. The conduit volume index increased from 20 mL/m
2 at rest to 24 mL/m2 at low exercise and stayed the same at peak exercise. Similarly, the conduit fraction increased from 54% at rest to 60% at low exercise ( P < 0.001) and did not change further with peak exercise. Although atrial function increased with exercise, the major contribution to the augmentation of LV stroke volume is LA conduit fraction, a marker of active ventricular relaxation. Furthermore, the major determinant of raising cardiac output during high-level exercise is heart rate. NEW & NOTEWORTHY Diseases of the left atrium (LA) are major sources of disability (e.g., strokes and fatigue), but its exercise physiology has been unstudied. Such knowledge may allow early recognition of disease and suggest therapies. We show that in normal subjects, low-level exercise decreases LA volume and increases its ejection fraction. However, these changes offset each other volumetrically, and the contribution to LV filling from a full to an empty LA (reservoir function) is static. Higher levels of exercise do not change LA reservoir contribution. Blood flowing directly from the pulmonary vein to LV (conduit flow) impelled by augmented LV active relaxation (suction) is the major source of a modest increase in LV stroke volume. The major source of increased cardiac output with exercise is heart rate. During all stages of exercise, the LA works hard but only to keep up. We believe that our findings provide an additional set of benchmarks through which to quantitate LA pathology and gauge its progression.- Published
- 2021
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267. Subxiphoid Hybrid Epicardial-Endocardial Atrial Fibrillation Ablation and LAA Ligation: Initial Sub-X Hybrid MAZE Registry Results.
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Ellis CR, Badhwar N, Tschopp D, Danter M, Jackson GG, Kerendi F, Walters T, Fang Q, Deuse T, Beygui R, and Lee RJ
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- Humans, Male, Middle Aged, Registries, Atrial Appendage diagnostic imaging, Atrial Appendage surgery, Atrial Fibrillation surgery, Catheter Ablation adverse effects, Pulmonary Veins surgery
- Abstract
Objectives: The aim of this study was to assess the safety and efficacy of a new subxiphoid hybrid epicardial-endocardial atrial fibrillation (AF) ablation and left atrial appendage (LAA) ligation approach for the treatment of persistent AF., Background: Surgical hybrid ablation procedures have shown promise for maintaining sinus rhythm versus catheter ablation but are associated with increased periprocedural adverse events., Methods: Patients with symptomatic persistent AF (n = 33, mean age 64 ± 9 years, 25 men) who had antiarrhythmic drug therapy or prior catheter ablation was unsuccessful were referred for hybrid epicardial-endocardial AF ablation and LAA exclusion. LAA closure was confirmed by transesophageal echocardiographic Doppler flow and/or computed tomographic angiography 1 to 3 months post-ligation. The incidence of atrial tachycardia or AF recurrence, LAA closure, thromboembolic events, and post-operative complications were assessed., Results: All 33 patients underwent successful LAA ligation with epicardial ablation of the posterior left atrial wall, as well as endocardial pulmonary vein isolation and cavotricuspid isthmus ablation. Freedom from atrial tachycardia or AF was 91% (20 of 22 patients) at 6 months, 90% (18 of 20 patients) at 12 months, 92% (11 of 12 patients) at 18 months, and 92% (11 of 12) at 24 months. There were no acute periprocedural complications (<7 days). Thirty-day adverse events included 2 patients with pericardial effusion requiring pericardiocentesis and 1 incisional hernia repair. There were no long-term complications, strokes, or deaths. LAA ligation was complete in 27 of 33 subjects (82%), with 6 subjects having leaks of <5 mm., Conclusions: Subxiphoid hybrid epicardial-endocardial ablation with LAA ligation is feasible, safe, and effective. Future prospective studies are needed to validate these initial findings., Competing Interests: Author Disclosures Dr. Lee is a consultant for and equity holder in SentreHEART/AtriCure. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)
- Published
- 2020
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268. Dyssynchrony and Fibrosis Persist After Resolution of Cardiomyopathy in a Swine Premature Ventricular Contraction Model.
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Walters TE, Szilagyi J, Alhede C, Sievers R, Fang Q, Olgin J, and Gerstenfeld EP
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- Animals, Fibrosis, Humans, Stroke Volume, Swine, Ventricular Function, Left, Cardiomyopathies, Ventricular Premature Complexes
- Abstract
Objectives: This study sought to prospectively study the development and then regression of premature ventricular contraction (PVC)-induced cardiomyopathy, with the hypothesis that structural left ventricular (LV) changes that are of potential clinical significance may endure beyond the period of exposure to PVCs., Background: Recovery of LV function after eradication of PVCs in PVC-induced cardiomyopathy is incompletely defined., Methods: Fifteen swine were exposed to: 1) 50% paced PVCs from the LV lateral epicardium for 12 weeks (LV PVC, n = 5); 2) no pacing for 12 weeks (Control, n = 5); or 3) 50% paced LV PVCs for 12 weeks followed by pacing cessation for 4 weeks (Recovery, n = 5). LV function was quantified biweekly in sinus rhythm with echocardiography. Dyssynchrony was measured from pressure-volume loops at baseline and terminal studies. LV fibrosis was quantified after sacrifice., Results: LV ejection fraction during sinus rhythm fell between baseline and terminal studies in the LV PVC group (65.8 ± 3.0 to 39.3 ± 3.2; p < 0.05), whereas there was no significant change in the Control group (69.6 ± 3.0 to 72.2 ± 3.0; p = NS) or after Recovery (64.5 ± 3.4% to 61.4 ± 3.4%; p = NS) groups. There was a significant increase in LV dyssynchrony measured during sinus rhythm between baseline and terminal studies in the LV PVC group (4.0 ± 1.5% to 9.0 ± 1.5%; p < 0.05); there was a similar increase in dyssynchrony that persisted 4 weeks after PVC cessation in the Recovery group (4.4 ± 1.7% to 12.8 ± 1.7%; p < 0.05). After sacrifice, percent fibrosis was higher in the LV PVC group compared with Control (5.7 ± 0.3% vs. 3.0 ± 0.3%; p < 0.05) and remained elevated in Recovery (4.1 ± 0.3% vs. 3.0 ± 0.3%; p < 0.05) despite return to baseline LV ejection fraction., Conclusions: In a swine model of PVC-induced cardiomyopathy, cessation of PVCs for 4 weeks leads to normalization of LV systolic function but significant changes in myocardial fibrosis and LV dyssynchrony during sinus rhythm persist., (Copyright © 2020 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)
- Published
- 2020
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269. A collective European experience with left atrial appendage suture ligation using the LARIAT+ device.
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Tilz RR, Fink T, Bartus K, Wong T, Vogler J, Nentwich K, Panniker S, Fang Q, Piorkowski C, Liosis S, Gaspar T, Sawan N, Metzner A, Nietlispach F, Maisano F, Lee RJ, Foran JP, Ouyang F, Sievert H, Deneke T, and Kuck KH
- Subjects
- Humans, Ligation, Prospective Studies, Sutures, Treatment Outcome, Atrial Appendage diagnostic imaging, Atrial Appendage surgery, Atrial Fibrillation diagnosis, Atrial Fibrillation surgery
- Abstract
Aims: We report the collective European experience of percutaneous left atrial appendage (LAA) suture ligation using the recent generation LARIAT+ suture delivery device., Methods and Results: A total of 141 patients with non-valvular atrial fibrillation and contraindication to oral anticoagulation (OAC), thrombo-embolic events despite OAC or electrical LAA isolation were enrolled at seven European hospitals to undergo LAA ligation. Patients were followed up by clinical visits and transoesophageal echocardiography (TOE) following LAA closure. Left atrial appendage ligation was completed in 138/141 patients (97.8%). Three patients did not undergo attempted deployment of the LARIAT device due to pericardial adhesion after previous epicardial ventricular tachycardia ablation (n = 1), a pericardial access-related complication (n = 1), and multiple posterior LAA lobes (n = 1). Serious 30-day procedural adverse events occurred in 4/141 patients (2.8%). There were two device-related LAA perforations (1.4%) not resulting in any corrective intervention as the LAA was completely sealed with the LARIAT. Minor adverse events occurred in 19 patients (13.5%), including two pericardial effusions due to procedure-related pericarditis requiring pericardiocentesis. Transoesophageal echocardiography was performed after LAA ligation in 103/138 patients (74.6%) after a mean of 181 ± 72 days. Complete LAA closure was documented in 100 patients (97.1%). Two patients (1.8% of patients with follow-up) experienced a transient ischaemic attack at 4 and 7 months follow-up, although there was no leak observed with TOE. There were two deaths during long-term follow-up which were both not device related., Conclusion: Initial experience with the LARIAT+ device demonstrates feasibility of LAA exclusion. Further larger prospective studies with longer follow-up are warranted., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2020. For permissions, please email: journals.permissions@oup.com.)
- Published
- 2020
- Full Text
- View/download PDF
270. Left ventricular mechanical dispersion predicts arrhythmic risk in mitral valve prolapse.
- Author
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Ermakov S, Gulhar R, Lim L, Bibby D, Fang Q, Nah G, Abraham TP, Schiller NB, and Delling FN
- Subjects
- Death, Sudden, Cardiac prevention & control, Electrocardiography, Ambulatory methods, Female, Fibrosis, Humans, Male, Middle Aged, Mitral Valve Prolapse pathology, Mitral Valve Prolapse physiopathology, Predictive Value of Tests, Risk Assessment methods, Echocardiography methods, Heart Ventricles diagnostic imaging, Heart Ventricles pathology, Heart Ventricles physiopathology, Mitral Valve Prolapse complications, Myocardial Contraction, Myocardium pathology, Ventricular Premature Complexes diagnosis, Ventricular Premature Complexes etiology
- Abstract
Objective: Bileaflet mitral valve prolapse (MVP) with either focal or diffuse myocardial fibrosis has been linked to ventricular arrhythmia and/or sudden cardiac arrest. Left ventricular (LV) mechanical dispersion by speckle-tracking echocardiography (STE) is a measure of heterogeneity of ventricular contraction previously associated with myocardial fibrosis. The aim of this study is to determine whether mechanical dispersion can identify MVP at higher arrhythmic risk., Methods: We identified 32 consecutive arrhythmic MVPs (A-MVP) with a history of complex ventricular ectopy on Holter/event monitor (n=23) or defibrillator placement (n=9) along with 27 MVPs without arrhythmic complications (NA-MVP) and 39 controls. STE was performed to calculate global longitudinal strain (GLS) as the average peak longitudinal strain from an 18-segment LV model and mechanical dispersion as the SD of the time to peak strain of each segment., Results: MVPs had significantly higher mechanical dispersion compared with controls (52 vs 42 ms, p=0.005) despite similar LV ejection fraction (62% vs 63%, p=0.42) and GLS (-19.7 vs -21, p=0.045). A-MVP and NA-MVP had similar demographics, LV ejection fraction and GLS (all p>0.05). A-MVP had more bileaflet prolapse (69% vs 44%, p=0.031) with a similar degree of mitral regurgitation (mostly trace or mild in both groups) (p>0.05). A-MVP exhibited greater mechanical dispersion when compared with NA-MVP (59 vs 43 ms, p=0.0002). Mechanical dispersion was the only significant predictor of arrhythmic risk on multivariate analysis (OR 1.1, 95% CI 1.02 to 1.11, p=0.006)., Conclusions: STE-derived mechanical dispersion may help identify MVP patients at higher arrhythmic risk., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2019. No commercial re-use. See rights and permissions. Published by BMJ.)
- Published
- 2019
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271. Embolic Stroke of Undetermined Source: A Population with Left Atrial Dysfunction.
- Author
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Meisel K, Yuan K, Fang Q, Bibby D, Lee R, and Schiller NB
- Subjects
- Aged, Case-Control Studies, Echocardiography, Stress methods, Echocardiography, Three-Dimensional, Exercise Test, Female, Heart Atria diagnostic imaging, Heart Diseases diagnostic imaging, Heart Diseases physiopathology, Humans, Intracranial Embolism diagnostic imaging, Male, Middle Aged, Predictive Value of Tests, Prognosis, Prospective Studies, Risk Assessment, Risk Factors, Stroke diagnostic imaging, Atrial Function, Left, Atrial Remodeling, Heart Atria physiopathology, Heart Diseases complications, Intracranial Embolism etiology, Stroke etiology
- Abstract
Background: Cryptogenic stroke, now defined as embolic stroke of undetermined source (ESUS), represents about a quarter of all ischemic strokes and the reoccurrence is high. Understanding this stroke subtype better would likely guide treatment recommendations. In this study, we tested the hypothesis that left atrial (LA) shape and function at rest, as well as with exercise, are abnormal compared to matched normal controls., Methods: The study design was prospective enrollment of ESUS subjects who underwent measurement of LA function at rest and exercise by 2D and 3D echocardiograms. The exercise portion of the study was conducted using a ramped supine bicycle protocol during which LA function was measured. Stroke subjects were matched with normal subjects by age, gender, and body surface area., Results: Over a 1-year enrollment period, 18 ESUS patients met inclusionary criteria and were studied. Their average age was 58 years old and 44% were female. ESUS subjects have larger LA end-diastolic volume at rest (14 versus 11 mL/m
2 , P = .04) and with exercise (11 versus 6 mL/m2 , P = .001) compared to normal controls. In ESUS, there was a lack of response to maximal exercise of LA function as measured by the LA ejection fraction (61% versus 73% P = .001) and the LA function index (.68 versus .82, P = .02). The 3D analysis showed spherical remodeling of the LA in ESUS. This remodeling was documented by the sphericity index, which was increased in both diastole (.40 versus .32, P = .02) and systole (.63 versus .71 P = .03)., Conclusions: In support of our hypothesis, we found that ESUS subjects have LA dysfunction and remodeling at rest and exercise in comparison to healthy, matched controls. Evaluation of the left atrium in this high-risk stroke subtype has potential to inform stroke prevention strategies and to suggest pathways for research., (Copyright © 2019 Elsevier Inc. All rights reserved.)- Published
- 2019
- Full Text
- View/download PDF
272. Combination of Left Atrial Appendage Isolation and Ligation to Treat Nonresponders of Pulmonary Vein Isolation.
- Author
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Fink T, Schlüter M, Heeger CH, Lemeš C, Maurer T, Reissmann B, Rottner L, Santoro F, Tilz RR, Alessandrini H, Rillig A, Mathew S, Wohlmuth P, Fang Q, Lee R, Ouyang F, Kuck KH, and Metzner A
- Subjects
- Aged, Arrhythmias, Cardiac epidemiology, Arrhythmias, Cardiac prevention & control, Atrial Fibrillation surgery, Female, Humans, Male, Middle Aged, Retrospective Studies, Atrial Appendage surgery, Catheter Ablation adverse effects, Catheter Ablation methods, Catheter Ablation statistics & numerical data, Postoperative Complications epidemiology, Postoperative Complications prevention & control, Pulmonary Veins surgery
- Abstract
Objectives: This study investigated the outcome of wide-area left atrial appendage isolation (WLAAI) and subsequent LAA ligation in patients with recurrent atrial arrhythmias after pulmonary vein isolation (PVI)., Background: LAA isolation and ligation may improve rhythm control and prevent LAA thrombus formation in patients with atrial fibrillation who do not respond to PVI., Methods: Patients (n = 31, mean age: 69.7 ± 7.8 years, 18 men) with arrhythmia recurrence after established PVI undergoing WLAAI with subsequent LAA ligation (LARIAT+ device) were studied. The incidence of arrhythmia recurrence, intracardiac thrombus formation, thromboembolic events, as well as changes in P-wave duration and P-wave dispersion were assessed., Results: All 31 patients underwent successful WLAAI, and successful LAA ligation was performed in 27 patients (87%). Over a median follow-up of 498 (interquartile range: 159 to 791) days, post-ligation arrhythmia recurrence was documented in 8 patients (26%). Kaplan-Meier estimate of 24-month arrhythmia-free survival after WLAAI/ligation was 69.7% (95% confidence interval: 53.9 to 90.1). Following WLAAI, LAA thrombus formation was seen in 11 patients (35.5%), but in no patient after LAA ligation. WLAAI/ligation significantly reduced P-wave duration (from 93 ± 20 ms to 72 ± 20 ms; p = 0.001) and P-wave dispersion (from 63 ± 37 ms to 38 ± 16 ms; p = 0.001)., Conclusions: WLAAI and subsequent LAA ligation in PVI nonresponders led to an estimated freedom from arrhythmia recurrence in 70% of the patients at 24 months. LAA ligation successfully prevented recurrence of cardiac thrombus formation in patients with WLAAI. Significant decreases in P-wave duration and P-wave dispersion occurred with WLAAI/ligation, suggesting favorable electrical remodelling., (Copyright © 2018 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)
- Published
- 2018
- Full Text
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273. Discrete microstructural cues for the attenuation of fibrosis following myocardial infarction.
- Author
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Pinney JR, Du KT, Ayala P, Fang Q, Sievers RE, Chew P, Delrosario L, Lee RJ, and Desai TA
- Subjects
- 3T3 Cells, Animals, Biocompatible Materials administration & dosage, Collagen analysis, Female, Fibroblasts cytology, Fibrosis, Methacrylates administration & dosage, Mice, Microtechnology, Polyethylene Glycols administration & dosage, Rats, Sprague-Dawley, Tissue Engineering, Biocompatible Materials therapeutic use, Methacrylates therapeutic use, Myocardial Infarction pathology, Myocardial Infarction therapy, Myocardium pathology, Polyethylene Glycols therapeutic use
- Abstract
Chronic fibrosis caused by acute myocardial infarction (MI) leads to increased morbidity and mortality due to cardiac dysfunction. We have developed a therapeutic materials strategy that aims to mitigate myocardial fibrosis by utilizing injectable polymeric microstructures to mechanically alter the microenvironment. Polymeric microstructures were fabricated using photolithographic techniques and studied in a three-dimensional culture model of the fibrotic environment and by direct injection into the infarct zone of adult rats. Here, we show dose-dependent down-regulation of expression of genes associated with the mechanical fibrotic response in the presence of microstructures. Injection of this microstructured material into the infarct zone decreased levels of collagen and TGF-β, increased elastin deposition and vascularization in the infarcted region, and improved functional outcomes after six weeks. Our results demonstrate the efficacy of these discrete anti-fibrotic microstructures and suggest a potential therapeutic materials approach for combatting pathologic fibrosis., (Copyright © 2014 Elsevier Ltd. All rights reserved.)
- Published
- 2014
- Full Text
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274. Proteomic identification of biomarkers of vascular injury.
- Author
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Huang NF, Kurpinski K, Fang Q, Lee RJ, and Li S
- Abstract
Predictive biomarkers may be beneficial for detecting, diagnosing, and assessing the risk of restenosis and vascular injury. We utilized proteomic profiling to identify protein markers in the blood following vascular injury, and corroborated the differential protein expression with immunological approaches. Rats underwent carotid artery injury, and plasma was collected after 2 or 5 weeks. Proteomic profiling was carried out by two-dimensional differential in-gel electrophoresis. The differentially expressed plasma proteins were identified by mass spectroscopy and confirmed by immunoblotting. Proteomic profiling by two-dimensional differential in-gel electrophoresis and mass spectroscopy revealed plasma proteins that were differentially expressed at 2 weeks after injury. Among the proteins identified included vitamin D binding protein (VDBP), aldolase A (aldo A), and apolipoproteinE (apoE). Immunoblotting results validated a significant reduction in these proteins in the plasma at 2 or 5 weeks after vascular injury, in comparison to control animals without vascular injury. These findings suggest that VDBP, aldo A, and apoE may be biomarkers for vascular injury, which will have important prognostic and diagnostic implications.
- Published
- 2011
275. Targeted in vivo extracellular matrix formation promotes neovascularization in a rodent model of myocardial infarction.
- Author
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Mihardja SS, Gao D, Sievers RE, Fang Q, Feng J, Wang J, Vanbrocklin HF, Larrick JW, Huang M, Dae M, and Lee RJ
- Subjects
- Animals, Antibodies administration & dosage, Antibodies therapeutic use, Collagen Type IV chemistry, Fibronectins chemistry, Immunoconjugates therapeutic use, Myocardial Infarction pathology, Myocardial Reperfusion Injury drug therapy, Myosin Heavy Chains immunology, Peptide Fragments therapeutic use, Rats, Rats, Sprague-Dawley, Drug Delivery Systems methods, Extracellular Matrix physiology, Myocardial Infarction drug therapy, Neovascularization, Physiologic drug effects, Peptide Fragments administration & dosage
- Abstract
Background: The extracellular matrix plays an important role in tissue regeneration. We investigated whether extracellular matrix protein fragments could be targeted with antibodies to ischemically injured myocardium to promote angiogenesis and myocardial repair., Methodology/principal Findings: Four peptides, 2 derived from fibronectin and 2 derived from Type IV Collagen, were assessed for in vitro and in vivo tendencies for angiogenesis. Three of the four peptides--Hep I, Hep III, RGD--were identified and shown to increase endothelial cell attachment, proliferation, migration and cell activation in vitro. By chemically conjugating these peptides to an anti-myosin heavy chain antibody, the peptides could be administered intravenously and specifically targeted to the site of the myocardial infarction. When administered into Sprague-Dawley rats that underwent ischemia-reperfusion myocardial infarction, these peptides produced statistically significantly higher levels of angiogenesis and arteriogenesis 6 weeks post treatment., Conclusions/significance: We demonstrated that antibody-targeted ECM-derived peptides alone can be used to sufficiently alter the extracellular matrix microenvironment to induce a dramatic angiogenic response in the myocardial infarct area. Our results indicate a potentially new non-invasive strategy for repairing damaged tissue, as well as a novel tool for investigating in vivo cell biology.
- Published
- 2010
- Full Text
- View/download PDF
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