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Roux H, Chomont N. Measuring Human Immunodeficiency Virus Reservoirs: Do We Need to Choose Between Quantity and Quality? J Infect Dis 2024; 229:635-643. [PMID: 37665978 PMCID: PMC10938203 DOI: 10.1093/infdis/jiad381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 08/17/2023] [Accepted: 08/31/2023] [Indexed: 09/06/2023] Open
Abstract
The persistence of latent viral genomes in people receiving antiretroviral therapy (ART) is the main obstacle to a cure for human immunodeficiency virus (HIV) infection. Viral reservoirs can be defined as cells harboring HIV genomes that have the ability to produce infectious virions. Precise quantification of the cellular reservoirs of HIV is challenging because these cells are rare, heterogeneous, and outnumbered by a larger number of cells carrying defective genomes. In addition, measuring the inducibility of these proviruses requires functional assays and remains technically difficult. The recent development of single-cell and single-viral genome approaches revealed additional layers of complexity: the cell subsets that harbor proviruses are heterogeneous and their ability to be induced is variable. A substantial fraction of intact HIV genomes may be permanently silenced after years of ART, revealing the underappreciated importance of induction assays. As such, a simple approach that would assess simultaneously the genetic intactness and the inducibility of the reservoir is still lacking. In this study, we review recent advances in the development of methods to quantify and characterize persistently infected cells, and we discuss how these findings can inform the design of future assays aimed at measuring the size of the intact and inducible HIV reservoir.
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Affiliation(s)
- Hélène Roux
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
| | - Nicolas Chomont
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Quebec, Canada
- Centre de Recherche du CHUM, Montreal, Quebec, Canada
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Gantner P, Buranapraditkun S, Pagliuzza A, Dufour C, Pardons M, Mitchell JL, Kroon E, Sacdalan C, Tulmethakaan N, Pinyakorn S, Robb ML, Phanuphak N, Ananworanich J, Hsu D, Vasan S, Trautmann L, Fromentin R, Chomont N. HIV rapidly targets a diverse pool of CD4 + T cells to establish productive and latent infections. Immunity 2023; 56:653-668.e5. [PMID: 36804957 PMCID: PMC10023508 DOI: 10.1016/j.immuni.2023.01.030] [Citation(s) in RCA: 29] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 10/15/2022] [Accepted: 01/25/2023] [Indexed: 02/19/2023]
Abstract
Upon infection, HIV disseminates throughout the human body within 1-2 weeks. However, its early cellular targets remain poorly characterized. We used a single-cell approach to retrieve the phenotype and TCR sequence of infected cells in blood and lymphoid tissue from individuals at the earliest stages of HIV infection. HIV initially targeted a few proliferating memory CD4+ T cells displaying high surface expression of CCR5. The phenotype of productively infected cells differed by Fiebig stage and between blood and lymph nodes. The TCR repertoire of productively infected cells was heavily biased, with preferential infection of previously expanded and disseminated clones, but composed almost exclusively of unique clonotypes, indicating that they were the product of independent infection events. Latent genetically intact proviruses were already archived early in infection. Hence, productive infection is initially established in a pool of phenotypically and clonotypically distinct T cells, and latently infected cells are generated simultaneously.
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Affiliation(s)
- Pierre Gantner
- Department of Microbiology, Infectiology and Immunology, Université de Montréal, Montreal, QC, Canada
| | - Supranee Buranapraditkun
- Department of Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand; Center of Excellence in Vaccine Research and Development, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Amélie Pagliuzza
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montreal, QC, Canada
| | - Caroline Dufour
- Department of Microbiology, Infectiology and Immunology, Université de Montréal, Montreal, QC, Canada
| | - Marion Pardons
- Department of Microbiology, Infectiology and Immunology, Université de Montréal, Montreal, QC, Canada
| | - Julie L Mitchell
- Vaccine and Gene Therapy Institute, Oregon Health & Science University, Beaverton, OR, USA
| | - Eugène Kroon
- SEARCH, Institute of HIV Research and Innovation, Bangkok, Thailand
| | - Carlo Sacdalan
- SEARCH, Institute of HIV Research and Innovation, Bangkok, Thailand
| | | | - Suteeraporn Pinyakorn
- Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, MD, USA; Henry M. Jackson Foundation for the Advancement of Military Medicine Inc., Bethesda, MD, USA
| | - Merlin L Robb
- Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, MD, USA; Henry M. Jackson Foundation for the Advancement of Military Medicine Inc., Bethesda, MD, USA
| | | | - Jintanat Ananworanich
- Department of Global Health, Amsterdam Medical Center, University of Amsterdam, Amsterdam, the Netherlands
| | - Denise Hsu
- Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, MD, USA; Henry M. Jackson Foundation for the Advancement of Military Medicine Inc., Bethesda, MD, USA
| | - Sandhya Vasan
- Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, MD, USA; Henry M. Jackson Foundation for the Advancement of Military Medicine Inc., Bethesda, MD, USA
| | - Lydie Trautmann
- Vaccine and Gene Therapy Institute, Oregon Health & Science University, Beaverton, OR, USA
| | - Rémi Fromentin
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montreal, QC, Canada
| | - Nicolas Chomont
- Department of Microbiology, Infectiology and Immunology, Université de Montréal, Montreal, QC, Canada; Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montreal, QC, Canada.
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O’Neill L, De Becker B, De Smet M, Le Polain De Waroux JB, Tavernier R, Duytschaever M, Knecht S. Atrial tachycardia occurring after a prior atrial fibrillation ablation procedure: Does non- inducibility matter? Front Cardiovasc Med 2022; 9:1073239. [PMID: 36568552 PMCID: PMC9769961 DOI: 10.3389/fcvm.2022.1073239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 11/14/2022] [Indexed: 12/12/2022] Open
Abstract
Recurrent atrial tachycardia (AT) is a common phenomenon after catheter ablation for AF, particularly in the setting of additional substrate ablation, with many studies demonstrating gap-related macro re-entrant AT (predominantly mitral and roof dependent) to be the dominant mechanism. Although multiple inducible ATs after ablation of the clinical AT are commonly described at repeat procedures, the optimal ablation strategy, and procedural endpoints are unclear in this setting. A recent randomized study addressing the question of non-inducibility as a procedural endpoint demonstrated no additional benefits to the ablation of all induced, non-clinical ATs, but it was limited by small numbers and high rates of non-inducibility. Nevertheless, once ablation of the clinical AT has been successfully performed, ensuring durable linear block and PV isolation may be sufficient for the prevention of further AT. Durable linear block, particularly at the mitral isthmus, is difficult to achieve but may be facilitated by the real-time evaluation of lesion quality and contiguity and the novel technique of vein of Marshall ethanol infusion. Large-scale, randomized trials are needed, nonetheless, to fully assess the optimal ablation strategy in the setting of recurrent AT post-AF ablation.
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Abstract
PREMISE Plant defenses are shaped by many factors, including herbivory, lifespan, and mating system. Predictions about plant defense and resistance are often based on resource allocation trade-offs with plant growth and reproduction. Additionally, two types of plant resistance, constitutive and induced resistance, are predicted to be evolutionary alternatives or redundant strategies. Given the variety of plant trait combinations and non-mutually exclusive predictions, examining resistance strategies in related species with different combinations of growth and reproductive traits is important to tease apart roles of plant traits and evolutionary history on plant resistance. METHODS Phylogenetic comparative methods were used to examine the potentially interacting influences of life history (annual/perennial), mating system (self-compatible/self-incompatible), and species growth rates on constitutive resistance and inducibility (additional resistance following damage) across Physalis species (Solanaceae). RESULTS Resistance was evolutionarily labile, and there was no correlation between constitutive resistance and inducibility. Annual species with fast growth rates displayed higher constitutive resistance, but growth rate did not affect constitutive resistance in perennials. In contrast, inducibility was negatively associated with species growth rate regardless of life history or mating system. CONCLUSIONS The different effects of plant life history and growth rate on constitutive resistance and inducibility indicate that defensive evolution is unconstrained by a trade-off between resistance types. The interactions among plant life history, growth, and herbivore resistance show that plant defense is shaped not only by herbivore environment, but also by plant traits that reflect a plant's evolutionary history and local selective pressures.
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Affiliation(s)
- Deidra J Jacobsen
- Department of Biology, 1001 E. Third Street, Indiana University, Bloomington, IN, 47405, USA
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van Staveren LN, van der Does WFB, Heida A, Taverne YJHJ, Bogers AJJC, de Groot NMS. AF Inducibility Is Related to Conduction Abnormalities at Bachmann's Bundle. J Clin Med 2021; 10:5536. [PMID: 34884237 DOI: 10.3390/jcm10235536] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 11/22/2021] [Accepted: 11/25/2021] [Indexed: 12/02/2022] Open
Abstract
We investigated whether patterns of activation at Bachmann’s bundle are related to AF inducibility. Epicardial mapping of Bachmann’s bundle during sinus rhythm was performed prior to cardiac surgery (192 electrodes, interelectrode distances: 2 mm). Compared to non-inducible patients (N = 20), patients with inducible AF (N = 34) had longer lines of conduction block (18(2–164) mm vs. 6(2–28) mm, p = 0.048), prolonged total activation time (55(28–143) ms vs. 46(24–73) ms, p = 0.012), multiple wavefronts entering Bachmann’s bundle more frequently (64% vs. 37%, p = 0.046) and more often areas of simultaneous activation (conduction velocity > 1.7 m/s, 45% vs. 16%, p = 0.038). These observations further support a relation between conduction abnormalities at Bachmann’s bundle and AF inducibility. The next step is to examine whether Bachmann’s bundle activation patterns can also be used to identify patients who will develop AF after cardiac surgery during both short- and long-term follow-up.
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Liu Z, Xia Y, Guo C, Li X, Fang P, Yin X, Yang X. Low-Voltage Zones as the Atrial Fibrillation Substrates: Relationship With Initiation, Perpetuation, and Termination. Front Cardiovasc Med 2021; 8:705510. [PMID: 34409078 PMCID: PMC8365032 DOI: 10.3389/fcvm.2021.705510] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 06/24/2021] [Indexed: 11/13/2022] Open
Abstract
Background: Low-voltage zones (LVZs) were usually targeted for ablation in atrial fibrillation (AF). However, its relationship with AF initiation, perpetuation, and termination remains to be studied. This study aimed to explore such relationships. Methods: A total of 126 consecutive AF patients were enrolled, including 71 patients for AF induction protocol and 55 patients for AF termination protocol. Inducible and sustainable AF were defined as induced AF lasting over 30 and 300 s, respectively. Terminable AF was defined as those that could be terminated into sinus rhythm within 1 h after ibutilide administration. Voltage mapping was performed in sinus rhythm for all patients. LVZ was quantified as the percentage of the LVZ area (LVZ%) to the left atrium surface area. Results: The rates of inducible, sustainable, and terminable AF were 29.6, 18.3, and 38.2%, respectively. Inducible AF patients had no significant difference in overall LVZ% compared with uninducible AF patients (10.2 ± 11.8 vs. 8.5 ± 12.6, p = 0.606), while sustainable and interminable AF patients had larger overall LVZ% than unsustainable (16.2 ± 11.5 vs. 0.5 ± 0.7, p < 0.001) and terminable AF patients (44.6 ± 26.4 vs. 26.3 ± 22.3, p < 0.05), respectively. The segmental LVZ distribution pattern was diverse in the different stages of AF. Segmental LVZ% difference was initially observed in the anterior wall for patients with inducible AF, and the septum was further affected in those with sustainable AF, and the roof, posterior wall, and floor were finally affected in those with interminable AF. Conclusions: The associations between LVZ with AF initiation, perpetuation, and termination were different depending on its size and distribution.
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Affiliation(s)
- Zheng Liu
- Heart Center, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China
| | - Yu Xia
- State Key Laboratory of Cardiovascular Disease, Cardiac Arrhythmia Center, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Changyan Guo
- Department of Cardiology, Xilin Gol League Central Hospital, Inner Mongolia, Xilinhot, China
| | - Xiaofeng Li
- State Key Laboratory of Cardiovascular Disease, Cardiac Arrhythmia Center, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Pihua Fang
- State Key Laboratory of Cardiovascular Disease, Cardiac Arrhythmia Center, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xiandong Yin
- Heart Center, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China
| | - Xinchun Yang
- Heart Center, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China
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Millenaar D, Becker N, Pavlicek V, Wintrich J, Böhm M, Mahfoud F, Ukena C. Inducibility of atrial fibrillation after catheter ablation predicts recurrences of atrial fibrillation: a meta-analysis. Pacing Clin Electrophysiol 2021; 44:667-676. [PMID: 33686680 DOI: 10.1111/pace.14216] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 02/28/2021] [Indexed: 01/29/2023]
Abstract
BACKGROUND Pulmonary vein isolation (PVI) is a component of standard care for patients with symptomatic atrial fibrillation (AF). Procedural inducibility of AF following PVI has been suggested as predictor of AF recurrence but is discussed controversially. This meta-analysis aimed at evaluating the relevance of electrophysiological inducibility of AF following PVI for future AF recurrences. METHODS A literature search of MEDLINE and Web of Science was performed until April 2020. Prospective trials of PVI in patients with AF and post-procedural atrial stimulation to test for inducibility of AF as well as adequate follow-up for AF recurrence (defined as AF >10 s to >10 min at follow-up) were included. Odds ratios (ORs) were analyzed using random-effects models. RESULTS A total of 11 trials with 1544 patients (follow-up 7-39 months, age 56 ± 6 years, predominantly male 74 ± 6%) were included. Inducibility of AF post-PVI was predictive for AF recurrence during follow-up (OR 2.08; 95% CI 1.25 to 3.46). Prediction for AF recurrence at follow-up was better for patients with paroxysmal AF (OR 4.06; 95% CI 1.39 to 11.91), stimulation in the CS (OR 2.82, 95% CI 1.17 to 6.79). A trend towards higher ORs was seen without the use of isoproterenol (OR 2.43; 95% CI 1.17 to 5.07), as well as few stimulations during induction and a short definition of AF in meta-regression analyses. CONCLUSIONS Electrophysiological inducibility of AF following PVI was predictive for future recurrence of AF, in particular in patients with paroxysmal AF, stimulation in only CS and no use of isoproterenol.
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Affiliation(s)
- Dominic Millenaar
- Department of Internal Medicine III, Cardiology, Angiology and Intensive Care Medicine, Saarland University Hospital, Homburg/Saar, Germany
| | - Nicolas Becker
- Personality Psychology and Psychological Assessment, Saarland University, Saarbrücken, Germany
| | - Valérie Pavlicek
- Department of Internal Medicine III, Cardiology, Angiology and Intensive Care Medicine, Saarland University Hospital, Homburg/Saar, Germany
| | - Jan Wintrich
- Department of Internal Medicine III, Cardiology, Angiology and Intensive Care Medicine, Saarland University Hospital, Homburg/Saar, Germany
| | - Michael Böhm
- Department of Internal Medicine III, Cardiology, Angiology and Intensive Care Medicine, Saarland University Hospital, Homburg/Saar, Germany
| | - Felix Mahfoud
- Department of Internal Medicine III, Cardiology, Angiology and Intensive Care Medicine, Saarland University Hospital, Homburg/Saar, Germany
| | - Christian Ukena
- Department of Internal Medicine III, Cardiology, Angiology and Intensive Care Medicine, Saarland University Hospital, Homburg/Saar, Germany
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Campbell T, Bennett RG, Garikapati K, Turnbull S, Bhaskaran A, De Silva K, Kumar S. Prognostic significance of extensive versus limited induction protocol during catheter ablation of scar-related ventricular tachycardia. J Cardiovasc Electrophysiol 2020; 31:2909-2919. [PMID: 32905634 DOI: 10.1111/jce.14740] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 09/02/2020] [Accepted: 09/03/2020] [Indexed: 12/11/2022]
Abstract
INTRODUCTION Testing for inducible ventricular tachycardia (VT) pre- and postablation forms the cornerstone of contemporary scar-related VT ablation procedures. There is significant heterogeneity in reported VT induction protocols. We examined the utility of an extensive induction protocol (up to 4 extra-stimuli [ES] ± burst ventricular pacing) compared to the current guideline-recommended protocol (up to 3ES, defined as limited induction protocol) in patients with scar-related VT. METHODS AND RESULTS Sixty-two patients (age: 64 ± 14 years; left ventricular ejection fraction: 37 ± 13%, ischemic cardiomyopathy: 31, nonischemic cardiomyopathy: 31) with at least one inducible VT were included. An extensive testing protocol induced 11%-17% more VTs, compared to the limited induction protocol before, and after the final ablation. VT recurred in 48% of patients during a mean follow up of 566 ± 428 days. Patients who were noninducible for any VT using the limited induction protocol had worse ventricular arrhythmia (VA)-free survival (12 months, 43% vs. 82%; p = .03) and worse survival free of VA, transplantation and mortality (12 months 46% vs. 82%; p = .02), compared to patients who were noninducible for any VT using the extensive induction protocol. CONCLUSIONS Between 11% and 17% of inducible VTs may be missed if 4ES and burst pacing are not performed in induction protocols before and after ablation. Noninducibility for any VT after an extensive induction protocol after the final ablation portends more favorable prognostic outcomes when compared with the current guideline-recommended induction protocol of up to 3ES. This data suggests that the adoption of an extensive induction protocol is of prognostic benefit after VT ablation.
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Affiliation(s)
- Timothy Campbell
- Department of Cardiology, Westmead Hospital, Sydney, Australia.,Westmead Applied Research Centre, University of Sydney, Sydney, New South Wales, Australia
| | - Richard G Bennett
- Department of Cardiology, Westmead Hospital, Sydney, Australia.,Westmead Applied Research Centre, University of Sydney, Sydney, New South Wales, Australia
| | | | - Samual Turnbull
- Department of Cardiology, Westmead Hospital, Sydney, Australia.,Westmead Applied Research Centre, University of Sydney, Sydney, New South Wales, Australia
| | | | - Kasun De Silva
- Department of Cardiology, Westmead Hospital, Sydney, Australia
| | - Saurabh Kumar
- Department of Cardiology, Westmead Hospital, Sydney, Australia.,Westmead Applied Research Centre, University of Sydney, Sydney, New South Wales, Australia
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Darma A, Daneschnejad SS, Gaspar T, Huo Y, Wetzel U, Dagres N, Husser D, Sommer P, Piorkowski C, Bollmann A, Hindricks G, Arya A. Role of inducibility and its dynamic change in the outcome of catheter ablation of atrial fibrillation: a single center prospective study. J Cardiovasc Electrophysiol 2020; 31:705-711. [PMID: 31943494 DOI: 10.1111/jce.14355] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 12/23/2019] [Accepted: 01/03/2020] [Indexed: 01/23/2023]
Abstract
BACKGROUND The role of atrial arrhythmia inducibility as an endpoint of catheter ablation of atrial fibrillation (AF) has been a controversial subject in many studies. Our goal is to evaluate the significance of inducibility, the impact of multiple sites or protocols of stimulation or the change in inducibility status in a prospective study including patients with AF undergoing first catheter ablation. METHODS We studied 170 consecutive patients with AF (62.9% paroxysmal) undergoing catheter ablation. All patients underwent two separate stimulation protocols before and after the ablation from the coronary sinus ostium and the left atrial appendage: burst pacing at 300, 250, 200 milliseconds (or until refractoriness) for 10 seconds and ramp decrementing from 300 to 200 milliseconds in increments of 10 milliseconds every three beats for 10 seconds. Inducibility was defined as any sustained AF or organized atrial tachycardia (AT) lasting >30 seconds. RESULTS We had AF/AT inducibility in 55 patients at baseline compared to 36 following ablation. After a mean of 41, 3 months follow-up, 115 patients were free of AF. Inducibility before or after the ablation or change in inducibility status did not influence AF recurrence. There were no significant differences regarding paroxysmal or persistent patients with AF. CONCLUSIONS Non-inducibility of atrial arrhythmia or change in inducibility status following pulmonary vein (PV) isolation and substrate modification are not associated with long-term freedom from recurrent arrhythmia. Therefore, the use of induction of an endpoint in AF ablation is limited.
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Affiliation(s)
- Angeliki Darma
- Department of Electrophysiology, Heart Center Leipzig at University of Leipzig, Leipzig, Germany
| | - Sait S Daneschnejad
- Department of Electrophysiology, Heart Center Leipzig at University of Leipzig, Leipzig, Germany
| | - Thomas Gaspar
- Department of Electrophysiology, Heart Center Leipzig at University of Leipzig, Leipzig, Germany
| | - Yan Huo
- Department of Electrophysiology, Heart Center Leipzig at University of Leipzig, Leipzig, Germany
| | - Ulrike Wetzel
- Department of Electrophysiology, Heart Center Leipzig at University of Leipzig, Leipzig, Germany
| | - Nikolaos Dagres
- Department of Electrophysiology, Heart Center Leipzig at University of Leipzig, Leipzig, Germany
| | - Daniela Husser
- Department of Electrophysiology, Heart Center Leipzig at University of Leipzig, Leipzig, Germany
| | - Philipp Sommer
- Department of Electrophysiology, Heart Center Leipzig at University of Leipzig, Leipzig, Germany
| | - Christopher Piorkowski
- Department of Electrophysiology, Heart Center Leipzig at University of Leipzig, Leipzig, Germany
| | - Andreas Bollmann
- Department of Electrophysiology, Heart Center Leipzig at University of Leipzig, Leipzig, Germany
| | - Gerhard Hindricks
- Department of Electrophysiology, Heart Center Leipzig at University of Leipzig, Leipzig, Germany
| | - Arash Arya
- Department of Electrophysiology, Heart Center Leipzig at University of Leipzig, Leipzig, Germany
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Johner N, Namdar M, Shah DC. Sustained and self-terminating atrial fibrillation induced immediately after pulmonary vein isolation exhibit differences in coronary sinus electrical activity from onset. J Cardiovasc Electrophysiol 2019; 31:150-159. [PMID: 31778260 DOI: 10.1111/jce.14296] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 10/16/2019] [Accepted: 10/27/2019] [Indexed: 11/28/2022]
Abstract
INTRODUCTION Little data exists on the electrophysiological differences between sustained atrial fibrillation (sAF; >5 minutes) vs self-terminating nonsustained AF (nsAF; <5 minutes). We sought to investigate the electrophysiological characteristics of coronary sinus (CS) activity during postpulmonary vein isolation (PVI) sAF vs nsAF. METHODS AND RESULTS We studied 142 patients post-PVI for paroxysmal AF (PAF). In a 50-patient subset, CS electrograms in the first 30 seconds of induced AF were analyzed manually. A custom-made algorithm for automated electrogram annotation was derived for validation on the whole patient set. In patients with sAF post-PVI, CS fractionated potentials were ablated. Manual analysis showed that patients with sAF exhibited higher activation pattern variability (2.1 vs 0.5 changes/sec; P < .001); fewer proximal-to-distal wavefronts (25 vs 61%; P < .001); fewer unidirectional wavefronts (60 vs 86%; P < .001); more pivot locations (4.3 vs 2.1; P < .001); shorter cycle lengths (190 vs 220 ms; P < .001); and shorter cumulative isoelectric segments (35 vs 44%; P = .045) compared to nsAF. These observations were confirmed on the whole study population by automated electrogram annotation and sample entropy computation (SampEn: 0.29 ± 0.15 in sAF vs 0.15 ± 0.05 in nsAF; P < .0001). The derived model predicted sAF with 78% sensitivity, 88% specificity; agreement with manual model: 88% (Cohen's kappa= 0.76). CS defragmentation resulted in AF termination or noninducibility in 49% of sAF. CONCLUSION In PAF patients post-PVI, induced sAF shows greater activation sequence variability, shorter cycle length, and higher SampEn in the CS compared to nsAF. Automated electrogram annotation confirmed these results and accurately distinguished self-terminating nsAF episodes from sAF based on 30-second recordings at AF onset.
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Affiliation(s)
- Nicolas Johner
- Cardiology Division, Geneva University Hospitals, Geneva, Switzerland
| | - Mehdi Namdar
- Cardiology Division, Geneva University Hospitals, Geneva, Switzerland
| | - Dipen C Shah
- Cardiology Division, Geneva University Hospitals, Geneva, Switzerland
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Hironobe N, Sairaku A, Nakano Y, Tokuyama T, Okamura S, Okubo Y, Shimizu W, Kihara Y. Cardiac electrophysiological characteristics of silent paroxysmal atrial fibrillation: What causes asymptomaticity? J Cardiovasc Electrophysiol 2019; 30:2716-2723. [PMID: 31588639 DOI: 10.1111/jce.14216] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 09/29/2019] [Accepted: 09/30/2019] [Indexed: 11/28/2022]
Abstract
BACKGROUND A diagnosis of silent paroxysmal atrial fibrillation (AF) is highly challenging due to its asymptomatic and intermittent nature. The goal of the present study was to clarify its asymptomaticity with the use of a comprehensive electrophysiological approach. METHODS We prospectively compared (a) 24-hour Holter monitoring data, (b) invasive cardiac electrophysiological properties, (c) AF inducibility, and (d) outcome of radiofrequency catheter ablation between patients with symptomatic paroxysmal AF and those with silent paroxysmal AF, defined as transient asymptomatic AF detected by chance. RESULTS Patients with silent paroxysmal AF (N = 57) were more likely than patients with symptomatic paroxysmal AF (N = 282) to be male (75.4% vs 56.7%; P = .009), and to have a previous stroke (17.5% vs 6.7%; P = .008), more prolonged atrio-His interval (114.9 ± 29.1 vs 105.5 ± 24.1 ms; P = .01), longer atrioventricular nodal effective refractory period (352.3 ± 103 vs 318.2 ± 77.2 ms; P = .007), slower Wenckebach cycle length (488.5 ± 83.9 vs 443.3 ± 74.9 ms; P < .001), and lower maximum heart rate during AF (128.7 ± 31.9 vs 143.9 ± 29.6 beats/min; P = .02). Atrial ectopy (median [interquartile range], 385 [88, 2430] vs 207 [73.8, 870.8] beats/24 h; P = .02) and pharmacological AF induction (66.7% vs 43.2%; P = .02) were more common in silent paroxysmal AF patients. There was no difference in the 1-year freedom from AF following the ablation between the two patient groups. CONCLUSIONS The more attenuated atrioventricular conduction properties in silent paroxysmal AF patients may explain their asymptomatic nature, and their higher likelihood of atrial arrhythmias may increase the chance to detect AF episodes. Whether or not they benefit from catheter ablation is uncertain.
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Affiliation(s)
- Naoya Hironobe
- Department of Cardiovascular Medicine, Hiroshima University, Hiroshima, Japan
| | - Akinori Sairaku
- Department of Cardiovascular Medicine, Hiroshima University, Hiroshima, Japan.,Department of Cardiovascular Medicine, Nippon Medical School, Tokyo, Japan
| | - Yukiko Nakano
- Department of Cardiovascular Medicine, Hiroshima University, Hiroshima, Japan
| | - Takehito Tokuyama
- Department of Cardiovascular Medicine, Hiroshima University, Hiroshima, Japan
| | - Sho Okamura
- Department of Cardiovascular Medicine, Hiroshima University, Hiroshima, Japan
| | - Yosaku Okubo
- Department of Cardiovascular Medicine, Hiroshima University, Hiroshima, Japan
| | - Wataru Shimizu
- Department of Cardiovascular Medicine, Nippon Medical School, Tokyo, Japan
| | - Yasuki Kihara
- Department of Cardiovascular Medicine, Hiroshima University, Hiroshima, Japan
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12
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Yoon N, Hong SN, Cho JG, Jeong HK, Lee KH, Park HW. Experimental verification of the value of the T peak -T end interval in ventricular arrhythmia inducibility in an early repolarization syndrome model. J Cardiovasc Electrophysiol 2019; 30:2098-2105. [PMID: 31424133 DOI: 10.1111/jce.14123] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2019] [Revised: 07/21/2019] [Accepted: 08/03/2019] [Indexed: 11/27/2022]
Abstract
INTRODUCTION In patients with early repolarization patterns on ECG, many researchers have studied to find predictors of fatal arrhythmia. However, there are no satisfying clinical predictors. We evaluated the value of the Tpeak -Tend interval on pseudo-ECG in canine myocardial wedge preparation models of early repolarization syndrome. METHODS AND RESULTS Transmural pseudo-ECG and endocardial/epicardial action potentials were recorded from coronary-perfused canine left ventricular wedge preparations (n = 34). The Ito agonist NS5806 (8-10 µM), the calcium channel blocker verapamil (3 µM) and acetylcholine (2-3 µM) were used to mimic the disease model. A ventricular arrhythmia induction test was performed. QTpeak , QTend , Tpeak -Tend , and Tpeak -Tend /QTend were measured at 15 to 20 minutes after the provocative agent infusion. Polymorphic ventricular tachycardias (pVT) developed in 23 of the 34 preparations (67%). The maximal values of Tpeak -Tend and Tpeak -Tend /QTend were recorded just before pVT induction. At baseline, without the provocative agents, Tpeak -Tend and Tpeak -Tend /QTend were not different between pVT-induced and pVT-noninduced preparations. The Tpeak -Tend of the pVT-induced preparations was longer than that of non-induced preparations (58 ± 26.8 msec vs 33 ± 6.8 msec, P < .001). The Tpeak -Tend /QTend of pVT- induced preparations was larger than that of noninduced preparations (0.220 ± 0.1017 vs 0.128 ± 0.0312, P < .001). The transmural and epicardial dispersion of repolarization of pVT-induced preparations were larger than those of pVT-noninduced preparations. The transmural dispersion of repolarization showed a positive correlation with Tpeak -Tend . CONCLUSION Tpeak -Tend predicted malignant ventricular arrhythmias in early repolarization syndrome models. Tpeak -Tend reflects the repolarization heterogeneity of ventricular myocardium.
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Affiliation(s)
- Namsik Yoon
- Heart Center of Chonnam National University Hospital, Gwangju, Republic of Korea
| | - Seo Na Hong
- Heart Center of Chonnam National University Hospital, Gwangju, Republic of Korea
| | - Jeong Gwan Cho
- Heart Center of Chonnam National University Hospital, Gwangju, Republic of Korea
| | - Hyung Ki Jeong
- Heart Center of Chonnam National University Hospital, Gwangju, Republic of Korea
| | - Ki Hong Lee
- Heart Center of Chonnam National University Hospital, Gwangju, Republic of Korea
| | - Hyung Wook Park
- Heart Center of Chonnam National University Hospital, Gwangju, Republic of Korea
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Norton NJ, Mok HP, Sharif F, Hirst JC, Lever AML. HIV Silencing and Inducibility Are Heterogeneous and Are Affected by Factors Intrinsic to the Virus. mBio 2019; 10:e00188-19. [PMID: 31239371 DOI: 10.1128/mBio.00188-19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Transcriptionally silent HIV proviruses form the major obstacle to eradicating HIV. Many studies of HIV latency have focused on the cellular mechanisms that maintain silencing of proviral DNA. Here we show that viral sequence variation affecting replicative ability leads to variable rates of silencing and ability to reactivate. We studied naturally occurring and engineered polymorphisms in a recently identified exonic splice enhancer (ESEtat) that regulates tat mRNA splicing and constructed viruses with increased (strain M1), reduced (strain M2), or completely absent (strain ERK) binding of splicing factors essential for optimal production of tat mRNA resulting in a corresponding change in Tat activity. The mutations affected viral replication, with M1 having wild-type (WT) kinetics, M2 exhibiting reduced kinetics, and ERK showing completely abrogated replication. Using single-round infection with green fluorescent protein (GFP)-expressing viruses to study proviral gene expression, we observed progressively greater rates of silencing relating to the degree of ESEtat disruption, with the WT strain at 53%, strain M2 at 69%, and strain ERK at 94%. By stimulating infected cells with a latency reversal agent (phorbol myristate acetate [PMA], panobinostat, or JQ1), we observed that the dose required to achieve 50% of the maximum signal was lowest in the WT, intermediate in M2, and highest in ERK, indicating progressively higher thresholds for reactivation. These results suggest that the ability of silent proviruses to reactivate from latency is variable and that minor differences in the viral sequence can alter the proportion of silenced viruses as well as the threshold required to induce silenced viruses to reactivate and express.IMPORTANCE A reservoir of infected cells in which the HIV genome is transcriptionally silent is acknowledged to be the principal barrier to eradicating the virus from an infected person. A number of cellular processes are implicated in this silencing; however, the viral factors that may contribute remain underexplored. Here we examined mutations altering the correct splicing of HIV gene products as a model to study whether differences in viral sequence can affect either the proportion of viruses that are active or silent or their ability to reactivate. We found that some naturally occurring variations result in viruses that are silenced at a higher rate and require a proportionally increased stimulus for reactivation from latency. These data suggest that the silencing and reactivation behavior of HIV exists in a spectrum, influenced by factors intrinsic to the virus.
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Skala T, Tudos Z, Moravec O, Hutyra M, Precek J, Skalova J, Klementova O, Zapletalova J, Taborsky M. Atrial fibrillation inducibility after pulmonary vein isolation under general anaesthesia. Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub 2019; 164:261-266. [PMID: 30829344 DOI: 10.5507/bp.2019.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 02/25/2019] [Indexed: 01/08/2023] Open
Abstract
AIMS Atrial fibrillation (AF) inducibility with rapid atrial pacing following AF ablation is associated with higher risk of AF recurrence. The predictive value of AF inducibility in paroxysmal AF patients after pulmonary vein isolation (PVI), done under general anaesthesia (GA), remains questionable since GA might alter AF inducibility and/or sustainability. METHODS Consecutive patients (n = 120) with paroxysmal AF without prior catheter ablation (CA) were enlisted in the study. All patients were ablated under GA. We have used a point-by-point CA and elimination of dormant conduction after adenosine in all patients. A predefined stimulation protocol was used to induce arrhythmias after PVI. Regular supraventricular tachycardias were mapped and ablated. Patients were divided into 3 subgroups - noninducible, inducible AF with spontaneous termination in five minutes, inducible AF without spontaneous termination. During 12 months of follow-up, all patients were examined four-times with 7-day ECG recordings. RESULTS There was no statistical difference between the three subgroups in a rate of arrhythmia recurrence (11.1 vs. 27.5 vs. 27.3%, P=0.387), despite a clear trend to a better success rate in the non-inducible group. The subgroups did not differ in left atrial (LA) diameter (41.0±6, 43.0±7, 42.0±5 mm, P=0.962) or in any other baseline parameter. CONCLUSION AF inducibility as well as presence or absence of its early spontaneous termination after PVI done under general anaesthesia in paroxysmal AF patients were not useful as predictors of procedural failure.
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Affiliation(s)
- Tomas Skala
- Department of Internal Medicine I - Cardiology, University Hospital Olomouc, Czech Republic
| | - Zbynek Tudos
- Department of Radiology, University Hospital Olomouc, Czech Republic
| | - Ondrej Moravec
- Department of Internal Medicine I - Cardiology, University Hospital Olomouc, Czech Republic
| | - Martin Hutyra
- Department of Internal Medicine I - Cardiology, University Hospital Olomouc, Czech Republic
| | - Jan Precek
- Department of Internal Medicine I - Cardiology, University Hospital Olomouc, Czech Republic
| | - Jitka Skalova
- Department of Anesthesiology and Intensive Care Medicine, University Hospital Olomouc, Czech Republic
| | - Olga Klementova
- Department of Anesthesiology and Intensive Care Medicine, University Hospital Olomouc, Czech Republic
| | - Jana Zapletalova
- Department of Biophysics, Faculty of Medicine and Dentistry, Palacky University Olomouc, Czech Republic
| | - Milos Taborsky
- Department of Internal Medicine I - Cardiology, University Hospital Olomouc, Czech Republic
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López-Goldar X, Villari C, Bonello P, Borg-Karlson AK, Grivet D, Zas R, Sampedro L. Inducibility of Plant Secondary Metabolites in the Stem Predicts Genetic Variation in Resistance Against a Key Insect Herbivore in Maritime Pine. Front Plant Sci 2018; 9:1651. [PMID: 30519249 PMCID: PMC6258960 DOI: 10.3389/fpls.2018.01651] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 10/24/2018] [Indexed: 05/20/2023]
Abstract
Resistance to herbivores and pathogens is considered a key plant trait with strong adaptive value in trees, usually involving high concentrations of a diverse array of plant secondary metabolites (PSM). Intraspecific genetic variation and plasticity of PSM are widely known. However, their ecology and evolution are unclear, and even the implication of PSM as traits that provide direct effective resistance against herbivores is currently questioned. We used control and methyl jasmonate (MJ) induced clonal copies of genotypes within families from ten populations of the main distribution range of maritime pine to exhaustively characterize the constitutive and induced profile and concentration of PSM in the stem phloem, and to measure insect herbivory damage as a proxy of resistance. Then, we explored whether genetic variation in resistance to herbivory may be predicted by the constitutive concentration of PSM, and the role of its inducibility to predict the increase in resistance once the plant is induced. We found large and structured genetic variation among populations but not between families within populations in resistance to herbivory. The MJ-induction treatment strongly increased resistance to the weevil in the species, and the genetic variation in the inducibility of resistance was significantly structured among populations, with greater inducibility in the Atlantic populations. Genetic variation in resistance was largely explained by the multivariate concentration and profile of PSM at the genotypic level, rather than by bivariate correlations with individual PSM, after accounting for genetic relatedness among genotypes. While the constitutive concentration of the PSM blend did not show a clear pattern of resistance to herbivory, specific changes in the chemical profile and the increase in concentration of the PSM blend after MJ induction were related to increased resistance. To date, this is the first example of a comprehensive and rigorous approach in which inducibility of PSM in trees and its implication in resistance was analyzed excluding spurious associations due to genetic relatedness, often overlooked in intraspecific studies. Here we provide evidences that multivariate analyses of PSM, rather than bivariate correlations, provide more realistic information about the potentially causal relationships between PSM and resistance to herbivory in pine trees.
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Affiliation(s)
- Xosé López-Goldar
- Misión Biológica de Galicia, Consejo Superior de Investigaciones Científicas, Pontevedra, Spain
- Department of Plant Pathology, The Ohio State University, Columbus, OH, United States
- Ecological Chemistry Group, Department of Chemistry, Royal Institute of Technology, Stockholm, Sweden
- Department of Forest Ecology and Genetics, Forest Research Centre, INIA, Madrid, Spain
| | - Caterina Villari
- Department of Plant Pathology, The Ohio State University, Columbus, OH, United States
- Daniel B. Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, United States
| | - Pierluigi Bonello
- Department of Plant Pathology, The Ohio State University, Columbus, OH, United States
| | - Anna Karin Borg-Karlson
- Ecological Chemistry Group, Department of Chemistry, Royal Institute of Technology, Stockholm, Sweden
| | - Delphine Grivet
- Department of Forest Ecology and Genetics, Forest Research Centre, INIA, Madrid, Spain
- Sustainable Forest Management Research Institute, INIA-University of Valladolid, Palencia, Spain
| | - Rafael Zas
- Misión Biológica de Galicia, Consejo Superior de Investigaciones Científicas, Pontevedra, Spain
| | - Luís Sampedro
- Misión Biológica de Galicia, Consejo Superior de Investigaciones Científicas, Pontevedra, Spain
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Otsuka T, Sagara K, Arita T, Yagi N, Suzuki S, Ikeda T, Yamashita T. Impact of electrophysiological and pharmacological non inducibility following pulmonary vein isolation in patients with paroxysmal and persistent atrial fibrillation. J Arrhythm 2018; 34:501-510. [PMID: 30327695 PMCID: PMC6174500 DOI: 10.1002/joa3.12085] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Accepted: 05/27/2018] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND Two methods for testing inducibility of atrial fibrillation (AF)-atrial pacing and isoproterenol infusion-have been proposed to determine the endpoint of catheter ablation. However, the utility of the combination for testing electrophysiological inducibility (EPI) and pharmacological inducibility (PHI) is unclear. METHODS After pulmonary vein isolation (PVI), inducibility of atrial tachyarrhythmia was assessed with the dual methods in 291 consecutive patients with AF (65% paroxysmal) undergoing initial catheter ablation. RESULTS The incidence of EPI was significantly higher in patients with persistent AF than paroxysmal AF (32.0% vs 11.7%, respectively, P < .001). The incidence of PHI was not significantly different between the two groups (25.2% vs 26.1%, respectively, P = .87). There was no significant difference in AF recurrence according to inducibility in paroxysmal AF. In persistent AF, however, patients achieving neither EPI nor PHI under PVI-only strategy had significantly lower rates of AF recurrence than those achieving either EPI or PHI and consequently requiring additional ablation for inducible atrial tachyarrhythmia (68.5% vs 49.0%, respectively; log-rank test, P = .022). In persistent AF, multivariate Cox regression analysis showed that achieving neither EPI nor PHI was a negative independent predictor of AF recurrence (HR 0.492, 95% CI 0.254-0.916, P = .026). CONCLUSIONS Achieving neither EPI nor PHI following PVI was associated with favorable outcome in patients with persistent AF. The combination of tests may discriminate patients responsive to the PVI-only strategy. Further selective approaches are necessary to improve outcome for inducible atrial tachyarrhythmia in patients with persistent AF.
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Affiliation(s)
- Takayuki Otsuka
- Department of Cardiovascular MedicineThe Cardiovascular InstituteTokyoJapan
- Department of Cardiovascular MedicineToho University Graduate School of MedicineTokyoJapan
| | - Koichi Sagara
- Department of Cardiovascular MedicineThe Cardiovascular InstituteTokyoJapan
| | - Takuto Arita
- Department of Cardiovascular MedicineThe Cardiovascular InstituteTokyoJapan
| | - Naoharu Yagi
- Department of Cardiovascular MedicineThe Cardiovascular InstituteTokyoJapan
| | - Shinya Suzuki
- Department of Cardiovascular MedicineThe Cardiovascular InstituteTokyoJapan
| | - Takanori Ikeda
- Department of Cardiovascular MedicineToho University Graduate School of MedicineTokyoJapan
| | - Takeshi Yamashita
- Department of Cardiovascular MedicineThe Cardiovascular InstituteTokyoJapan
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Essebag V, Joza J, Nery PB, Doucette S, Nault I, Rivard L, Gula L, Deyell M, Raymond JM, Lane C, Sapp JL. Prognostic Value of Non inducibility on Outcomes of Ventricular Tachycardia Ablation: A VANISH Substudy. JACC Clin Electrophysiol 2018; 4:911-919. [PMID: 30025692 DOI: 10.1016/j.jacep.2018.03.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 03/19/2018] [Accepted: 03/21/2018] [Indexed: 11/17/2022]
Abstract
OBJECTIVES This study sought to evaluate the predictive value of noninducibility on long-term outcomes. BACKGROUND The traditional endpoint for catheter ablation of ventricular tachycardia (VT) is noninducibility of VT by programmed stimulation; however, the definition of inducibility remains variable and its prognostic value limited by nonstandardized periprocedural antiarrhythmic drug therapy and implantable cardioverter-defibrillator programming in prior observational studies. The VANISH trial randomized patients with prior myocardial infarction and VT to ablation (with an endpoint of noninducibility of VT ≥300 ms after ablation) versus antiarrhythmic drug escalation. METHODS Patients enrolled in the VANISH study randomized to catheter ablation were included. The relationship between post-ablation inducibility and the primary composite endpoint (death, VT storm >30 days, or appropriate implantable cardioverter-defibrillator shock >30 days) was assessed using a time-to-event analysis, adjusting for other clinical and procedural characteristics. RESULTS A total of 129 patients from the ablation arm were included in the primary analysis, of which 51 were noninducible post-ablation compared with 78 who had inducible VT or in whom inducibility testing was not performed. There were no significant baseline characteristic or procedural differences except for increased implantable cardioverter-defibrillator shocks before randomization in the noninducible group. In multivariate analysis, inducibility significantly increased the risk of death, appropriate shock, or VT storm after 30 days (HR: 1.87; p = 0.017). CONCLUSIONS Inducibility of any VT post-ablation was associated with an increased risk of the composite endpoint in the VANISH trial. A randomized trial is required to confirm whether more aggressive ablation targeting faster induced VTs (<300 ms) can improve outcomes.
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Affiliation(s)
- Vidal Essebag
- McGill University Health Centre Research Institute, Montreal, Canada; Hôpital Sacré-Coeur de Montréal, Montreal, Canada.
| | - Jacqueline Joza
- McGill University Health Centre Research Institute, Montreal, Canada
| | - Pablo B Nery
- Research Methods Unit, University of Ottawa Heart Institute, Ottawa, Canada
| | - Steve Doucette
- Department of Community Health and Epidemiology, Dalhousie University, Halifax, Canada
| | - Isabelle Nault
- Institute Universitaire de Cardiologie et de Pneumologie de Quebec, Quebec, Canada
| | | | | | | | | | - Chris Lane
- Royal Jubilee Hospital, Victoria, Canada
| | - John L Sapp
- Department of Medicine, QEII Health Sciences Centre and Dalhousie University, Halifax, Canada
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Köhler A, Maag D, Veyrat N, Glauser G, Wolfender JL, Turlings TCJ, Erb M. Within-plant distribution of 1,4-benzoxazin-3-ones contributes to herbivore niche differentiation in maize. Plant Cell Environ 2015; 38:1081-93. [PMID: 25293400 DOI: 10.1111/pce.12464] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Revised: 09/25/2014] [Accepted: 09/25/2014] [Indexed: 05/07/2023]
Abstract
Plant defences vary in space and time, which may translate into specific herbivore-foraging patterns and feeding niche differentiation. To date, little is known about the effect of secondary metabolite patterning on within-plant herbivore foraging. We investigated how variation in the major maize secondary metabolites, 1,4-benzoxazin-3-one derivatives (BXDs), affects the foraging behaviour of two leaf-chewing herbivores. BXD levels varied substantially within plants. Older leaves had higher levels of constitutive BXDs while younger leaves were consistently more inducible. These differences were observed independently of plant age, even though the concentrations of most BXDs declined markedly in older plants. Larvae of the well-adapted maize pest Spodoptera frugiperda preferred and grew better on young inducible leaves irrespective of plant age, while larvae of the generalist Spodoptera littoralis preferred and tended to grow better on old leaves. In BXD-free mutants, the differences in herbivore weight gain between old and young leaves were absent for both species, and leaf preferences of S. frugiperda were attenuated. In contrast, S. littoralis foraging patterns were not affected. In summary, our study shows that plant secondary metabolites differentially affect performance and foraging of adapted and non-adapted herbivores and thereby likely contribute to feeding niche differentiation.
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Affiliation(s)
- Angela Köhler
- Laboratory of Fundamental and Applied Research in Chemical Ecology, University of Neuchâtel, Neuchâtel, 2000, Switzerland
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Amouyal M. From adjacent activation in Escherichia coli and DNA cyclization to eukaryotic enhancers: the elements of a puzzle. Front Genet 2014; 5:371. [PMID: 25404937 PMCID: PMC4217526 DOI: 10.3389/fgene.2014.00371] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Accepted: 10/04/2014] [Indexed: 11/13/2022] Open
Abstract
Deoxyribonucleic acid cyclization, Escherichia coli lac repressor binding to two spaced lac operators and repression enhancement can be successfully used for a better understanding of the conditions required for interaction between eukaryotic enhancers and the machinery of transcription initiation. Chronologically, the DNA looping model has first accounted for the properties initially defining enhancers, i.e., independence of action with distance or orientation with respect to the start of transcription. It has also predicted enhancer activity or its disruption at short distance (site orientation, alignment between promoter and enhancer sites), with high-order complexes of protein, or with transcription factor concentrations close or different from the wild-type situation. In another step, histones have been introduced into the model to further adapt it to eukaryotes. They in fact favor DNA cyclization in vitro. The resulting DNA compaction might explain the difference counted in base pairs in the distance of action between eukaryotic transcription enhancers and prokaryotic repression enhancers. The lac looping system provides a potential tool for analysis of this discrepancy and of chromatin state directly in situ. Furthermore, as predicted by the model, the contribution of operators O2 and O3 to repression of the lac operon clearly depends on the lac repressor level in the cell and is prevented in strains overproducing lac repressor. By extension, gene regulation especially that linked to cell fate, should also depend on transcription factor levels, providing a potential tool for cellular therapy. In parallel, a new function of the O1–O3 loop completes the picture of lac repression. The O1–O3 loop would at the same time ensure high efficiency of repression, inducibility through the low-affinity sites and limitation of the level of repressor through self-repression of the lac repressor. Last, the DNA looping model can be successfully adapted to the enhancer auxiliary elements known as insulators.
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Affiliation(s)
- Michèle Amouyal
- Interactions à Distance, Centre National de la Recherche Scientifique Paris, France
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