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Li E, van der Heyden MAG. The network of cardiac K IR2.1: its function, cellular regulation, electrical signaling, diseases and new drug avenues. Naunyn Schmiedebergs Arch Pharmacol 2024:10.1007/s00210-024-03116-5. [PMID: 38683369 DOI: 10.1007/s00210-024-03116-5] [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] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Accepted: 04/19/2024] [Indexed: 05/01/2024]
Abstract
The functioning of the human heart relies on complex electrical and communication systems that coordinate cardiac contractions and sustain rhythmicity. One of the key players contributing to this intricate system is the KIR2.1 potassium ion channel, which is encoded by the KCNJ2 gene. KIR2.1 channels exhibit abundant expression in both ventricular myocytes and Purkinje fibers, exerting an important role in maintaining the balance of intracellular potassium ion levels within the heart. And by stabilizing the resting membrane potential and contributing to action potential repolarization, these channels have an important role in cardiac excitability also. Either gain- or loss-of-function mutations, but also acquired impairments of their function, are implicated in the pathogenesis of diverse types of cardiac arrhythmias. In this review, we aim to elucidate the system functions of KIR2.1 channels related to cellular electrical signaling, communication, and their contributions to cardiovascular disease. Based on this knowledge, we will discuss existing and new pharmacological avenues to modulate their function.
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Affiliation(s)
- Encan Li
- Department of Medical Physiology, Division Heart & Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM, Utrecht, Netherlands
| | - Marcel A G van der Heyden
- Department of Medical Physiology, Division Heart & Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM, Utrecht, Netherlands.
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Bloothooft M, Pennings HJM, van der Heyden MAG. The Utrecht University Honours Program review project: example based scientific publishing training aimed at bachelor medical students. BMC Med Educ 2024; 24:115. [PMID: 38321518 PMCID: PMC10848494 DOI: 10.1186/s12909-024-05098-7] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 01/25/2024] [Indexed: 02/08/2024]
Abstract
INTRODUCTION Medical undergraduate students receive limited education on scholarly publishing. However, publishing experiences during this phase are known to influence study and career paths. The medical bachelor Honours Program (HP) at Utrecht University initiated a hands-on writing and publishing course, which resulted in nine reviews published in internationally peer reviewed academic journals. We wanted to share the project set-up, explore the academic development of the participating students and determine the impact of the reviews on the scientific community. METHODS Thirty-one out of 50 alumni completed a digital retrospective questionnaire on for example, development of skills and benefit for their studies and career. Publication metrics of the HP review papers were retrieved from Web of Science. RESULTS This hands-on project provides a clear teaching method on academic writing and scholarly publishing in the bachelor medical curriculum. Participants were able to obtain and improve writing and publishing skills. The output yielded well-recognized scientific papers and valuable learning experiences. 71% of the participating students published at least one additional paper following this project, and 55% of the students indicated the project influenced their academic study and/or career path. Nine manuscripts were published in journals with an average impact factor of 3.56 and cited on average 3.73 times per year. DISCUSSION This course might inspire other medical educators to incorporate similar projects successfully into their curriculum. To this end, a number of recommendations with regard to supervision, time investment and group size are given.
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Affiliation(s)
- Meye Bloothooft
- Department of Medical Physiology, Division Heart and Lungs of University Medical Center Utrecht, Yalelaan 50, 3584 CM, Utrecht, The Netherlands
| | - Helena J M Pennings
- Utrecht Center for Research and Development of Health Professions Education, University Medical Center Utrecht, Utrecht, The Netherlands
- Department Learning and Workforce Development, Netherlands Organization for Applied Scientific Research (TNO), Soesterberg, The Netherlands
| | - Marcel A G van der Heyden
- Department of Medical Physiology, Division Heart and Lungs of University Medical Center Utrecht, Yalelaan 50, 3584 CM, Utrecht, The Netherlands.
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Bloothooft M, Verbruggen B, Seibertz F, van der Heyden MAG, Voigt N, de Boer TP. Recording ten-fold larger I Kr conductances with automated patch clamping using equimolar Cs + solutions. Front Physiol 2024; 15:1298340. [PMID: 38328302 PMCID: PMC10847579 DOI: 10.3389/fphys.2024.1298340] [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] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Accepted: 01/09/2024] [Indexed: 02/09/2024] Open
Abstract
Background: The rapid delayed rectifier potassium current (IKr) is important for cardiac repolarization and is most often involved in drug-induced arrhythmias. However, accurately measuring this current can be challenging in human-induced pluripotent stem cell (hiPSC)-derived cardiomyocytes because of its small current density. Interestingly, the ion channel conducting IKr, hERG channel, is not only permeable to K+ ions but also to Cs+ ions when present in equimolar concentrations inside and outside of the cell. Methods: In this study, IhERG was measured from Chinese hamster ovary (CHO)-hERG cells and hiPSC-CM using either Cs+ or K+ as the charge carrier. Equimolar Cs+ has been used in the literature in manual patch-clamp experiments, and here, we apply this approach using automated patch-clamp systems. Four different (pre)clinical drugs were tested to compare their effects on Cs+- and K+-based currents. Results: Using equimolar Cs+ solutions gave rise to approximately ten-fold larger hERG conductances. Comparison of Cs+- and K+-mediated currents upon application of dofetilide, desipramine, moxifloxacin, or LUF7244 revealed many similarities in inhibition or activation properties of the drugs studied. Using equimolar Cs+ solutions gave rise to approximately ten-fold larger hERG conductances. In hiPSC-CM, the Cs+-based conductance is larger compared to the known K+-based conductance, and the Cs+ hERG conductance can be inhibited similarly to the K+-based conductance. Conclusion: Using equimolar Cs+ instead of K+ for IhERG measurements in an automated patch-clamp system gives rise to a new method by which, for example, quick scans can be performed on effects of drugs on hERG currents. This application is specifically relevant when such experiments are performed using cells which express small IKr current densities in combination with small membrane capacitances.
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Affiliation(s)
- Meye Bloothooft
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, Netherlands
| | - Bente Verbruggen
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, Netherlands
| | - Fitzwilliam Seibertz
- Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Georg-August University Göttingen, Göttingen, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany
- Cluster of Excellence “Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells” (MBExC), University of Göttingen, Göttingen, Germany
- Nanion Technologies GmbH, Munich, Germany
| | - Marcel A. G. van der Heyden
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, Netherlands
| | - Niels Voigt
- Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Georg-August University Göttingen, Göttingen, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany
- Cluster of Excellence “Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells” (MBExC), University of Göttingen, Göttingen, Germany
| | - Teun P. de Boer
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, Netherlands
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Loen V, Van Weperen VYH, Beekman HDM, Van Bavel JJA, Meijborg VMF, Van der Waal JG, Coronel R, van der Heyden MAG, Vos MA. High-rate pacing suppresses Torsade de Pointes arrhythmias and reduces spatial dispersion of repolarization in the chronic AV-block dog model. Front Physiol 2023; 14:1330230. [PMID: 38179141 PMCID: PMC10765543 DOI: 10.3389/fphys.2023.1330230] [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: 10/30/2023] [Accepted: 12/04/2023] [Indexed: 01/06/2024] Open
Abstract
Background: An electrical storm of Torsade de Pointes arrhythmias (TdP) can be reproducibly induced in the anesthetized chronic AV-block (CAVB) dog by infusion of the IKr-blocker dofetilide. Earlier studies showed that these arrhythmias 1) arise from locations with high spatial dispersion in repolarization (SDR) and 2) can be suppressed by high-rate pacing. We examined whether suppression of TdP by high-rate pacing is established through a decrease in SDR in the CAVB dog. Methods: Dofetilide (25 μg/kg in 5 min) was administered to 5 anesthetized CAVB dogs to induce TdP arrhythmias. During the experiments, animals were continuously paced from the right ventricular apex at 50 beats/minute (RVA50). Upon TdP occurrence and conversion, RVA pacing was consecutively set to 100, 80 and 60 beats/minute for 2 min, referred to as pacing blocks. To determine the additional anti-arrhythmic effects of HRP over defibrillation alone, the number of arrhythmic events and SDR at RVA100 were compared to data from three previously conducted experiments, in which dogs underwent the same experimental protocol but were paced at RVA60 upon TdP occurrence (RVA60retro). In all experiments, recordings included surface electrocardiogram and mapping by 56 intramural needles, each recording four electrograms, evenly inserted into the ventricular walls and septum. For each pacing block, the number of ectopic beats (EB), and TdP severity were scored. SDR was quantified as the average difference in repolarization time within four squared needles (SDRcubic). Results: In 4 out of 5 animals, pacing at RVA100 suppressed TdP occurrence. One dog could not be converted by defibrillation after the initial TdP. Compared to RVA50, pacing at RVA100, but not RVA80 and RVA60, significantly reduced the TdP score (78 ± 33 vs. 0 ± 0, p < 0.05 and vs. 12.5 ± 25 and 25 ± 50, both p > 0.05). The reduction in TdP score was reflected by a significant decrease in SDRcubic (125 ± 46 ms before TdP vs. 49 ± 18 ms during RVA100, p < 0.05), and SDR was smaller than in the RVA60retro animals (101 ± 52 ms, p < 0.05 vs. RVA100). Conclusion: In CAVB dogs, high-rate pacing effectively suppresses TdP, which, at least in part, results from a spatial homogenization of cardiac repolarization, as reflected by a decrease in SDR.
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Affiliation(s)
- Vera Loen
- Department of Medical Physiology, University Medical Center Utrecht, Utrecht, Netherlands
| | | | | | - Joanne J. A. Van Bavel
- Department of Medical Physiology, University Medical Center Utrecht, Utrecht, Netherlands
| | - Veronique M. F. Meijborg
- Department of Clinical and Experimental Cardiology, Academic Medical Center, Amsterdam, Netherlands
| | - Jeanne G. Van der Waal
- Department of Clinical and Experimental Cardiology, Academic Medical Center, Amsterdam, Netherlands
| | - Ruben Coronel
- Department of Clinical and Experimental Cardiology, Academic Medical Center, Amsterdam, Netherlands
| | | | - Marc A. Vos
- Department of Medical Physiology, University Medical Center Utrecht, Utrecht, Netherlands
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Loen V, Smoczynska A, Aranda Hernandez A, Scheerder COS, van der Linde BHR, Beekman HDM, Cervera-Barea A, Boink GJJ, Sluijter JPG, van der Heyden MAG, Meine M, Vos MA. Automatic measurement of short-term variability of repolarization to indicate ventricular arrhythmias in a porcine model of cardiac ischaemia. Europace 2023; 25:euad341. [PMID: 37949832 PMCID: PMC10661665 DOI: 10.1093/europace/euad341] [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: 09/01/2023] [Accepted: 10/30/2023] [Indexed: 11/12/2023] Open
Abstract
AIMS An automated method for determination of short-term variability (STV) of repolarization on intracardiac electrograms (STV-ARIauto) has previously been developed for arrhythmic risk monitoring by cardiac implantable devices, and has proved effective in predicting ventricular arrhythmias (VA) and guiding preventive high-rate pacing (HRP) in a canine model. Current study aimed to assess (i) STV-ARIauto in relation to VA occurrence and secondarily (ii-a) to confirm the predictive capacity of STV from the QT interval and (ii-b) explore the effect of HRP on arrhythmic outcomes in a porcine model of acute myocardial infarction (MI). METHODS AND RESULTS Myocardial infarction was induced in 15 pigs. In 7/15 pigs, STV-QT was assessed at baseline, occlusion, 1 min before VA, and just before VA. Eight of the 15 pigs were additionally monitored with an electrogram catheter in the right ventricle, underwent echocardiography at baseline and reperfusion, and were randomized to paced or control group. Paced group received atrial pacing at 20 beats per min faster than sinus rhythm 1 min after occlusion. Short-term variability increased prior to VA in both STV modalities. The percentage change in STV from baseline to successive timepoints correlated well between STV-QT and STV-ARIauto. High-rate pacing did not improve arrhythmic outcomes and was accompanied by a stronger decrease in ejection fraction. CONCLUSION STV-ARIauto values increase before VA onset, alike STV-QT in a porcine model of MI, indicating imminent arrhythmias. This highlights the potential of automatic monitoring of arrhythmic risk by cardiac devices through STV-ARIauto and subsequently initiates preventive strategies. Continuous HRP during onset of acute MI did not improve arrhythmic outcomes.
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Affiliation(s)
- Vera Loen
- Department of Medical Physiology, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
| | - Agnieszka Smoczynska
- Department of Cardiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | | | - Coert O S Scheerder
- CRM EMEA Medical Science, Medtronic Bakken Research Center, Maastricht, The Netherlands
| | - Britt H R van der Linde
- Department of Medical Physiology, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
| | - Henriëtte D M Beekman
- Department of Medical Physiology, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
| | - Aina Cervera-Barea
- Experimental Cardiology Laboratory, Department of Cardiology, University Medical Center Utrecht, Utrecht, The Netherlands
- Department of Medical Biology, Amsterdam Cardiovascular Sciences, Amsterdam University Medical Center, Amsterdam, The Netherlands
| | - Gerard J J Boink
- Department of Medical Biology, Amsterdam Cardiovascular Sciences, Amsterdam University Medical Center, Amsterdam, The Netherlands
- Department of Cardiology, Amsterdam Cardiovascular Sciences, Amsterdam University Medical Center, Amsterdam, The Netherlands
| | - Joost P G Sluijter
- Experimental Cardiology Laboratory, Department of Cardiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Marcel A G van der Heyden
- Department of Medical Physiology, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
| | - Mathias Meine
- Department of Cardiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Marc A Vos
- Department of Medical Physiology, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
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van Bavel JJA, Beekman HDM, Smoczyńska A, van der Heyden MAG, Vos MA. I Ks Activator ML277 Mildly Affects Repolarization and Arrhythmic Outcome in the CAVB Dog Model. Biomedicines 2023; 11:biomedicines11041147. [PMID: 37189765 DOI: 10.3390/biomedicines11041147] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 04/09/2023] [Accepted: 04/10/2023] [Indexed: 05/17/2023] Open
Abstract
Long QT syndrome type 1 with affected IKs is associated with a high risk for developing Torsade de Pointes (TdP) arrhythmias and eventually sudden cardiac death. Therefore, it is of high interest to explore drugs that target IKs as antiarrhythmics. We examined the antiarrhythmic effect of IKs channel activator ML277 in the chronic atrioventricular block (CAVB) dog model. TdP arrhythmia sensitivity was tested in anesthetized mongrel dogs (n = 7) with CAVB in series: (1) induction experiment at 4 ± 2 weeks CAVB: TdP arrhythmias were induced with our standardized protocol using dofetilide (0.025 mg/kg), and (2) prevention experiment at 10 ± 2 weeks CAVB: the antiarrhythmic effect of ML277 (0.6-1.0 mg/kg) was tested by infusion for 5 min preceding dofetilide. ML277: (1) temporarily prevented repolarization prolongation induced by dofetilide (QTc: 538 ± 65 ms at induction vs. 393 ± 18 ms at prevention, p < 0.05), (2) delayed the occurrence of the first arrhythmic event upon dofetilide (from 129 ± 28 s to 180 ± 51 s, p < 0.05), and (3) decreased the arrhythmic outcome with a significant reduction in the number of TdP arrhythmias, TdP score, arrhythmia score and total arrhythmic events (from 669 ± 132 to 401 ± 228, p < 0.05). IKs channel activation by ML277 temporarily suppressed QT interval prolongation, delayed the occurrence of the first arrhythmic event and reduced the arrhythmic outcome in the CAVB dog model.
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Affiliation(s)
- Joanne J A van Bavel
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, 3584 Utrecht, The Netherlands
| | - Henriëtte D M Beekman
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, 3584 Utrecht, The Netherlands
| | - Agnieszka Smoczyńska
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, 3584 Utrecht, The Netherlands
| | - Marcel A G van der Heyden
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, 3584 Utrecht, The Netherlands
| | - Marc A Vos
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, 3584 Utrecht, The Netherlands
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Li E, Kool W, Woolschot L, van der Heyden MAG. Chronic Propafenone Application Increases Functional K IR2.1 Expression In Vitro. Pharmaceuticals (Basel) 2023; 16:ph16030404. [PMID: 36986503 PMCID: PMC10056987 DOI: 10.3390/ph16030404] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 02/28/2023] [Accepted: 03/04/2023] [Indexed: 03/30/2023] Open
Abstract
Expression and activity of inwardly rectifying potassium (KIR) channels within the heart are strictly regulated. KIR channels have an important role in shaping cardiac action potentials, having a limited conductance at depolarized potentials but contributing to the final stage of repolarization and resting membrane stability. Impaired KIR2.1 function causes Andersen-Tawil Syndrome (ATS) and is associated with heart failure. Restoring KIR2.1 function by agonists of KIR2.1 (AgoKirs) would be beneficial. The class 1c antiarrhythmic drug propafenone is identified as an AgoKir; however, its long-term effects on KIR2.1 protein expression, subcellular localization, and function are unknown. Propafenone's long-term effect on KIR2.1 expression and its underlying mechanisms in vitro were investigated. KIR2.1-carried currents were measured by single-cell patch-clamp electrophysiology. KIR2.1 protein expression levels were determined by Western blot analysis, whereas conventional immunofluorescence and advanced live-imaging microscopy were used to assess the subcellular localization of KIR2.1 proteins. Acute propafenone treatment at low concentrations supports the ability of propafenone to function as an AgoKir without disturbing KIR2.1 protein handling. Chronic propafenone treatment (at 25-100 times higher concentrations than in the acute treatment) increases KIR2.1 protein expression and KIR2.1 current densities in vitro, which are potentially associated with pre-lysosomal trafficking inhibition.
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Affiliation(s)
- Encan Li
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
| | - Willy Kool
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
| | - Liset Woolschot
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
| | - Marcel A G van der Heyden
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
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van Bavel JJA, Beekman HDM, van Weperen VYH, van der Linde HJ, van der Heyden MAG, Vos MA. I Ks inhibitor JNJ303 prolongs the QT interval and perpetuates arrhythmia when combined with enhanced inotropy in the CAVB dog. Eur J Pharmacol 2022; 932:175218. [PMID: 36007604 DOI: 10.1016/j.ejphar.2022.175218] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 08/10/2022] [Accepted: 08/14/2022] [Indexed: 11/20/2022]
Abstract
INTRODUCTION Impaired IKs induced by drugs or due to a KCNQ1 mutation, diagnosed as long QT syndrome type 1 (LQT1) prolongs the QT interval and predisposes the heart to Torsade de Pointes (TdP) arrhythmias. The anesthetized chronic AV block (CAVB) dog is inducible for TdP after remodeling and IKr inhibitor dofetilide. We tested the proarrhythmic effect of IKs inhibition in the CAVB dog, and the proarrhythmic role of increased contractility herein. METHODS Dofetilide-inducible animals were included to test the proarrhythmic effect of 1) IKs inhibition by JNJ303 (0.63 mg/kg/10min i.v.; n = 4), 2) IKs inhibition combined with enhanced inotropy (ouabain, 0.045 mg/kg/1min i.v.; n = 6), and 3) the washout period of the anesthetic regime (n = 10). RESULTS JNJ303 prolonged the QTc interval (from 477 ± 53 ms to 565 ± 14 ms, P < 0.02) resembling standardized dofetilide-induced QTc prolongation. Single ectopic beats (n = 4) and ventricular tachycardia (VT) (n = 3) were present, increasing the arrhythmia score (AS) from 1.0 ± 0 to 7.1 ± 6.5. JNJ303 combined with ouabain increased contractile parameters (LVdP/dtmax from 1725 ± 273 to 4147 ± 611 mmHg/s, P < 0.01). Moreover, TdP arrhythmias were induced in 4/6 dogs and AS increased from 1.0 ± 0 to 20.2 ± 19.0 after JNJ303 and ouabain (P < 0.05). Finally, TdP arrhythmias were induced in 4/10 dogs during the anesthesia washout period and the AS increased from 1.1 ± 0.3 to 9.2 ± 11.2. CONCLUSION Mimicking LQT1 using IKs inhibitor JNJ303 prolongs the QTc interval and triggers ectopic beats and non-sustained VT in the CAVB dog. Induction of the more severe arrhythmic events (TdP) demands a combination of IKs inhibition with enhanced inotropy or ending the anesthetic regime.
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Affiliation(s)
- Joanne J A van Bavel
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Henriëtte D M Beekman
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Valerie Y H van Weperen
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Henk J van der Linde
- Janssen Research & Development, Division of Janssen Pharmaceutica NV, Beerse, Belgium
| | - Marcel A G van der Heyden
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Utrecht, the Netherlands.
| | - Marc A Vos
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Utrecht, the Netherlands
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Li E, Loen V, van Ham WB, Kool W, van der Heyden MAG, Takanari H. Quantitative Analysis of the Cytoskeleton's Role in Inward Rectifier K IR 2.1 Forward and Backward Trafficking. Front Physiol 2022; 12:812572. [PMID: 35145427 PMCID: PMC8821923 DOI: 10.3389/fphys.2021.812572] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 12/23/2021] [Indexed: 11/13/2022] Open
Abstract
Alteration of the inward rectifier current IK1, carried by KIR2.1 channels, affects action potential duration, impacts resting membrane stability and associates with cardiac arrhythmias. Congenital and acquired KIR2.1 malfunction frequently associates with aberrant ion channel trafficking. Cellular processes underlying trafficking are intertwined with cytoskeletal function. The extent to which the cytoskeleton is involved in KIR2.1 trafficking processes is unknown. We aimed to quantify the dependence of KIR2.1 trafficking on cytoskeleton function. GFP or photoconvertible Dendra2 tagged KIR2.1 constructs were transfected in HEK293 or HeLa cells. Photoconversion of the Dendra2 probe at the plasma membrane and subsequent live imaging of trafficking processes was performed by confocal laser-scanning microscopy. Time constant of green fluorescent recovery (τg,s) represented recruitment of new KIR2.1 at the plasma membrane. Red fluorescent decay (τr,s) represented internalization of photoconverted KIR2.1. Patch clamp electrophysiology was used to quantify IKIR2.1. Biochemical methods were used for cytoskeleton isolation and detection of KIR2.1-cytoskeleton interactions. Cytochalasin B (20 μM), Nocodazole (30 μM) and Dyngo-4a (10 nM) were used to modify the cytoskeleton. Chloroquine (10 μM, 24 h) was used to impair KIR2.1 breakdown. Cytochalasin B and Nocodazole, inhibitors of actin and tubulin filament formation respectively, strongly inhibited the recovery of green fluorescence at the plasma membrane suggestive for inhibition of KIR2.1 forward trafficking [τg,s 13 ± 2 vs. 131 ± 31* and 160 ± 40* min, for control, Cytochalasin B and Nocodazole, respectively (*p < 0.05 vs. control)]. Dyngo-4a, an inhibitor of dynamin motor proteins, strongly slowed the rate of photoconverted channel internalization, whereas Nocodazole and Cytochalasin B had less effect [τr,s 20 ± 2 vs. 87 ± 14*, 60 ± 16 and 64 ± 20 min (*p < 0.05 vs. control)]. Cytochalasin B treatment (20 μM, 24 h) inhibited IKIR2.1. Chloroquine treatment (10 μM, 24 h) induced intracellular aggregation of KIR2.1 channels and enhanced interaction with the actin/intermediate filament system (103 ± 90 fold; p < 0.05 vs. control). Functional actin and tubulin cytoskeleton systems are essential for forward trafficking of KIR2.1 channels, whereas initial backward trafficking relies on a functional dynamin system. Chronic disturbance of the actin system inhibits KIR2.1 currents. Internalized KIR2.1 channels become recruited to the cytoskeleton, presumably in lysosomes.
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Affiliation(s)
- Encan Li
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Utrecht, Netherlands
| | - Vera Loen
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Utrecht, Netherlands
| | - Willem B van Ham
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Utrecht, Netherlands
| | - Willy Kool
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Utrecht, Netherlands
| | - Marcel A G van der Heyden
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Utrecht, Netherlands
| | - Hiroki Takanari
- Department of Interdisciplinary Researches for Medicine and Photonics, Institute of Post-LED Photonics, University of Tokushima, Tokushima, Japan
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Houtman MJC, Friesacher T, Chen X, Zangerl-Plessl EM, van der Heyden MAG, Stary-Weinzinger A. Development of I KATP Ion Channel Blockers Targeting Sulfonylurea Resistant Mutant K IR6.2 Based Channels for Treating DEND Syndrome. Front Pharmacol 2022; 12:814066. [PMID: 35095528 PMCID: PMC8795863 DOI: 10.3389/fphar.2021.814066] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 12/23/2021] [Indexed: 11/13/2022] Open
Abstract
Introduction: DEND syndrome is a rare channelopathy characterized by a combination of developmental delay, epilepsy and severe neonatal diabetes. Gain of function mutations in the KCNJ11 gene, encoding the KIR6.2 subunit of the IKATP potassium channel, stand at the basis of most forms of DEND syndrome. In a previous search for existing drugs with the potential of targeting Cantú Syndrome, also resulting from increased IKATP, we found a set of candidate drugs that may also possess the potential to target DEND syndrome. In the current work, we combined Molecular Modelling including Molecular Dynamics simulations, with single cell patch clamp electrophysiology, in order to test the effect of selected drug candidates on the KIR6.2 WT and DEND mutant channels. Methods: Molecular dynamics simulations were performed to investigate potential drug binding sites. To conduct in vitro studies, KIR6.2 Q52R and L164P mutants were constructed. Inside/out patch clamp electrophysiology on transiently transfected HEK293T cells was performed for establishing drug-channel inhibition relationships. Results: Molecular Dynamics simulations provided insight in potential channel interaction and shed light on possible mechanisms of action of the tested drug candidates. Effective IKIR6.2/SUR2a inhibition was obtained with the pore-blocker betaxolol (IC50 values 27-37 μM). Levobetaxolol effectively inhibited WT and L164P (IC50 values 22 μM) and Q52R (IC50 55 μM) channels. Of the SUR binding prostaglandin series, travoprost was found to be the best blocker of WT and L164P channels (IC50 2-3 μM), while Q52R inhibition was 15-20% at 10 μM. Conclusion: Our combination of MD and inside-out electrophysiology provides the rationale for drug mediated IKATP inhibition, and will be the basis for 1) screening of additional existing drugs for repurposing to address DEND syndrome, and 2) rationalized medicinal chemistry to improve IKATP inhibitor efficacy and specificity.
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Affiliation(s)
- Marien J C Houtman
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, Netherlands
| | - Theres Friesacher
- Department of Pharmaceutical Sciences, Division of Pharmacology and Toxicology, University of Vienna, Vienna, Austria
| | - Xingyu Chen
- Department of Pharmaceutical Sciences, Division of Pharmacology and Toxicology, University of Vienna, Vienna, Austria
| | - Eva-Maria Zangerl-Plessl
- Department of Pharmaceutical Sciences, Division of Pharmacology and Toxicology, University of Vienna, Vienna, Austria
| | - Marcel A G van der Heyden
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, Netherlands
| | - Anna Stary-Weinzinger
- Department of Pharmaceutical Sciences, Division of Pharmacology and Toxicology, University of Vienna, Vienna, Austria
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11
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Paulus MC, Wijnhoven AM, Maessen GC, Blankensteijn SR, van der Heyden MAG. Does vitamin B12 deficiency explain psychiatric symptoms in recreational nitrous oxide users? A narrative review. Clin Toxicol (Phila) 2021; 59:947-955. [PMID: 34348072 DOI: 10.1080/15563650.2021.1938107] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Background Recreational use of nitrous oxide (N2O) is associated with many side effects, of which neurological complications are most common. Nitrous oxide abuse is also associated with psychiatric symptoms, but these have received less attention so far. Vitamin B12 deficiency may play a role in the development of these psychiatric symptoms.Aims To explore the relationship among the occurrence of recreational nitrous oxide-induced psychiatric symptoms, accompanying neurological symptoms, vitamin B12 status and choice of treatment.Methods A retrospective search for case reports was conducted across multiple databases (Pubmed, Embase, Web of Science, PsycINFO and CINAHL). Keywords included variants of "nitrous oxide", "case report" and "abuse". No restrictions to language or publication date were applied.Results The search retrieved 372 articles. A total of 25 case reports were included, representing 31 patients with psychiatric complications following nitrous oxide abuse. The most often reported symptoms were: hallucinations (n = 16), delusions (n = 11), and paranoia (n = 11). When neurological symptoms were present, patients were treated more frequently with vitamin B12 supplementation.Conclusions This review highlights the need to recognize that psychiatric symptoms may appear in association with nitrous oxide use. Approximately half of the cases that presented with nitrous oxide-induced psychiatric complaints did not show neurological symptoms, and their vitamin B12 concentration was often within the hospital's reference range. Psychiatrists and emergency physicians should be aware of isolated psychiatric symptoms caused by recreational nitrous oxide abuse. We suggest asking all patients with new psychiatric symptoms about nitrous oxide use and protocolizing the management of nitrous oxide-induced psychiatric symptoms.
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Affiliation(s)
- Michelle C Paulus
- CRU + Master, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Anjali M Wijnhoven
- CRU + Master, University Medical Center Utrecht, Utrecht, The Netherlands
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12
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Abstract
Publications baring falsified and fabricated images appear frequently in the primary literature. Industrialized forms of image forgery as practiced by the so-called paper mills worsen the current situation even further. Good education and awareness within the scientific society are essential to create an environment in which honesty and trust are the prime values in experimental research. Here I focus on the detection of publication fraud and provide some examples and advice. Finally, my views on the future of fraud detection and prevention are given.
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Affiliation(s)
- Marcel A G van der Heyden
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM, Utrecht, The Netherlands. .,Graduate School of Life Sciences, Utrecht University, Utrecht, The Netherlands.
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13
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Aalten M, Bakhuis CFJ, Asaggau I, Wulfse M, van Binsbergen MF, Arntz ERAN, Troenokarso MF, Oediet Doebe JLR, Mahamuud U, Belbachir L, Meurs M, Kovalenko NA, van der Heyden MAG. The clinical course and treatment of black mamba ( Dendroaspis polylepis) envenomations: a narrative review. Clin Toxicol (Phila) 2021; 59:860-868. [PMID: 34219550 DOI: 10.1080/15563650.2021.1943427] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
CONTEXT The black mamba (Dendroaspis polylepis) is, due to its extremely toxic venom, one of the most dangerous snake species in Sub-Saharan Africa. A D. polylepis bite is a medical emergency and requires adequate action to prevent severe complications. However, there are no comprehensive reviews available based on clinical cases, and no readily accessible guidelines for standardized treatment. Therefore, we aim to provide an overview regarding the currently available clinical literature on D. polylepis envenomations; in order to promote knowledge on symptomatology and treatment options. METHODS We searched for cases reporting humans bitten by D. polylepis in PubMed, Embase, Scopus, and Sabinet. We searched the reference lists of all eligible articles for additional articles. After quality assessment, 29 cases were included in this review. We used descriptive analysis to create an overview of the collected parameters. DISCUSSION Among the included case reports and case series, D. polylepis envenomations most frequently resulted in decreased respiratory function, sweating and paralysis. The onset of symptoms usually occurred within 60 minutes. Neurological symptoms occurred more often than symptoms of autonomic dysfunction. In the reported cases most patients (26/29) received antivenom and most survived (25/29). We recommend the reporting of additional structured case reports to improve future analyses on the clinical course of envenomations, in order to improve public health response to D. polylepis envenomations.
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Affiliation(s)
- Mark Aalten
- Honours Program CRU + Bachelor, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Carsten F J Bakhuis
- Honours Program CRU + Bachelor, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Ilias Asaggau
- Honours Program CRU + Bachelor, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Maaike Wulfse
- Honours Program CRU + Bachelor, University Medical Center Utrecht, Utrecht, The Netherlands
| | | | - Eran R A N Arntz
- Honours Program CRU + Bachelor, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Max F Troenokarso
- Honours Program CRU + Bachelor, University Medical Center Utrecht, Utrecht, The Netherlands
| | | | - Ubah Mahamuud
- Honours Program CRU + Bachelor, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Leila Belbachir
- Honours Program CRU + Bachelor, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Myrthe Meurs
- Honours Program CRU + Bachelor, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Nastya A Kovalenko
- Honours Program CRU + Bachelor, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Marcel A G van der Heyden
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Utrecht, The Netherlands
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14
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van Weperen VYH, Dunnink A, Bossu A, Beekman JDM, Meijborg VMF, de Bakker JMT, Coronel R, Varkevisser R, van der Heyden MAG, Vos MA. Severe Bradycardia Increases the Incidence and Severity of Torsade de Pointes Arrhythmias by Augmenting Preexistent Spatial Dispersion of Repolarization in the CAVB Dog Model. Front Physiol 2021; 12:642083. [PMID: 33981248 PMCID: PMC8110054 DOI: 10.3389/fphys.2021.642083] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [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: 12/15/2020] [Accepted: 03/17/2021] [Indexed: 11/13/2022] Open
Abstract
INTRODUCTION Torsade de pointes arrhythmias (TdP) in the chronic atrioventricular block (CAVB) dog model result from proarrhythmic factors, which trigger TdP and/or reinforce the arrhythmic substrate. This study investigated electrophysiological and arrhythmogenic consequences of severe bradycardia for TdP. METHODS Dofetilide (25 μg/kg per 5 min) was administered to eight anesthetized, idioventricular rhythm (IVR) remodeled CAVB dogs in two serial experiments: once under 60 beats per minute (bpm), right ventricular apex paced (RVA60) conditions, once under more bradycardic IVR conditions. Recordings included surface electrocardiogram and short-term variability (STV) of repolarization from endocardial unipolar electrograms. TdP inducibility (three or more episodes within 10 min after start of dofetilide) and arrhythmic activity scores (AS) were established. Mapping experiments in 10 additional dogs determined the effect of lowering rate on STV and spatial dispersion of repolarization (SDR) in baseline. RESULTS IVR-tested animals had longer baseline RR-interval (1,403 ± 271 ms) and repolarization intervals than RVA60 animals. Dofetilide increased STV similarly under both rhythm strategies. Nevertheless, TdP inducibility and AS were higher under IVR conditions (6/8 and 37 ± 27 vs. 1/8 and 8 ± 12 in RVA60, respectively, both p < 0.05). Mapping: Pacing from high (128 ± 10 bpm) to middle (88 ± 10 bpm) to experimental rate (61 ± 3 bpm) increased all electrophysiological parameters, including interventricular dispersion, due to steeper left ventricular restitution curves, and intraventricular SDR: maximal cubic dispersion from 60 ± 14 (high) to 69 ± 17 (middle) to 84 ± 22 ms (p < 0.05 vs. high and middle rate). CONCLUSION In CAVB dogs, severe bradycardia increases the probability and severity of arrhythmic events by heterogeneously causing electrophysiological instability, which is mainly reflected in an increased spatial, and to a lesser extent temporal, dispersion of repolarization.
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Affiliation(s)
| | - Albert Dunnink
- Department of Medical Physiology, Universitair Medisch Centrum Utrecht, Utrecht, Netherlands
| | - Alexandre Bossu
- Department of Medical Physiology, Universitair Medisch Centrum Utrecht, Utrecht, Netherlands
| | - Jet D. M. Beekman
- Department of Medical Physiology, Universitair Medisch Centrum Utrecht, Utrecht, Netherlands
| | - Veronique M. F. Meijborg
- Department of Clinical and Experimental Cardiology, Amsterdam UMC Locatie AMC, Amsterdam, Netherlands
| | - Jacques M. T. de Bakker
- Department of Clinical and Experimental Cardiology, Amsterdam UMC Locatie AMC, Amsterdam, Netherlands
| | - Ruben Coronel
- Department of Clinical and Experimental Cardiology, Amsterdam UMC Locatie AMC, Amsterdam, Netherlands
| | - Rosanne Varkevisser
- Department of Medical Physiology, Universitair Medisch Centrum Utrecht, Utrecht, Netherlands
| | | | - Marc A. Vos
- Department of Medical Physiology, Universitair Medisch Centrum Utrecht, Utrecht, Netherlands
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15
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Loen V, Vos MA, van der Heyden MAG. The canine chronic atrioventricular block model in cardiovascular preclinical drug research. Br J Pharmacol 2021; 179:859-881. [PMID: 33684961 PMCID: PMC9291585 DOI: 10.1111/bph.15436] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [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: 10/28/2020] [Revised: 02/23/2021] [Accepted: 02/28/2021] [Indexed: 12/29/2022] Open
Abstract
Ventricular cardiac arrhythmia is a life threating condition arising from abnormal functioning of many factors in concert. Animal models mirroring human electrophysiology are essential to predict and understand the rare pro- and anti-arrhythmic effects of drugs. This is very well accomplished by the canine chronic atrioventricular block (CAVB) model. Here we summarize canine models for cardiovascular research, and describe the development of the CAVB model from its beginning. Understanding of the structural, contractile and electrical remodelling processes following atrioventricular (AV) block provides insight in the many factors contributing to drug-induced arrhythmia. We also review all safety pharmacology studies, efficacy and mechanistic studies on anti-arrhythmic drugs in CAVB dogs. Finally, we compare pros and cons with other in vivo preclinical animal models. In view of the tremendous amount of data obtained over the last 100 years from the CAVB dog model, it can be considered as man's best friend in preclinical drug research.
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Affiliation(s)
- Vera Loen
- Department of Medical Physiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Marc A Vos
- Department of Medical Physiology, University Medical Center Utrecht, Utrecht, The Netherlands
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16
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Chauhan VS, Martínez JP, van der Heyden MAG. Commentary: Increased Beat-to-Beat Variability of T-Wave Heterogeneity Measured From Standard 12-Lead Electrocardiogram Is Associated With Sudden Cardiac Death: A Case-Control Study. Front Physiol 2020; 11:598314. [PMID: 33192614 PMCID: PMC7604440 DOI: 10.3389/fphys.2020.598314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 09/08/2020] [Indexed: 11/22/2022] Open
Affiliation(s)
- Vijay S Chauhan
- Division of Cardiology, Peter Munk Cardiac Centre, University Health Network, Toronto, ON, Canada
| | - Juan Pablo Martínez
- Aragón Institute of Engineering Research, IIS Aragón, Universidad de Zaragoza, Zaragoza, Spain.,Biomedical Research Networking Center in Bioengineering, Biomaterials, and Nanomedicine (CIBER-BBN), Zaragoza, Spain
| | - Marcel A G van der Heyden
- Division of Heart & Lungs, Department of Medical Physiology, University Medical Center Utrecht, Utrecht, Netherlands
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17
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Zangerl-Plessl EM, Qile M, Bloothooft M, Stary-Weinzinger A, van der Heyden MAG. Disease Associated Mutations in K IR Proteins Linked to Aberrant Inward Rectifier Channel Trafficking. Biomolecules 2019; 9:biom9110650. [PMID: 31731488 PMCID: PMC6920955 DOI: 10.3390/biom9110650] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 10/22/2019] [Accepted: 10/23/2019] [Indexed: 12/28/2022] Open
Abstract
The ubiquitously expressed family of inward rectifier potassium (KIR) channels, encoded by KCNJ genes, is primarily involved in cell excitability and potassium homeostasis. Channel mutations associate with a variety of severe human diseases and syndromes, affecting many organ systems including the central and peripheral neural system, heart, kidney, pancreas, and skeletal muscle. A number of mutations associate with altered ion channel expression at the plasma membrane, which might result from defective channel trafficking. Trafficking involves cellular processes that transport ion channels to and from their place of function. By alignment of all KIR channels, and depicting the trafficking associated mutations, three mutational hotspots were identified. One localized in the transmembrane-domain 1 and immediately adjacent sequences, one was found in the G-loop and Golgi-export domain, and the third one was detected at the immunoglobulin-like domain. Surprisingly, only few mutations were observed in experimentally determined Endoplasmic Reticulum (ER)exit-, export-, or ER-retention motifs. Structural mapping of the trafficking defect causing mutations provided a 3D framework, which indicates that trafficking deficient mutations form clusters. These “mutation clusters” affect trafficking by different mechanisms, including protein stability.
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Affiliation(s)
- Eva-Maria Zangerl-Plessl
- Department of Pharmacology and Toxicology, University of Vienna, 1090 Vienna, Austria; (E.-M.Z.-P.); (A.S.-W.)
| | - Muge Qile
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, 3584 CM Utrecht, The Netherlands; (M.Q.); (M.B.)
| | - Meye Bloothooft
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, 3584 CM Utrecht, The Netherlands; (M.Q.); (M.B.)
| | - Anna Stary-Weinzinger
- Department of Pharmacology and Toxicology, University of Vienna, 1090 Vienna, Austria; (E.-M.Z.-P.); (A.S.-W.)
| | - Marcel A. G. van der Heyden
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, 3584 CM Utrecht, The Netherlands; (M.Q.); (M.B.)
- Correspondence: ; Tel.: +31-887558901
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18
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Qile M, Beekman HDM, Sprenkeler DJ, Houtman MJC, van Ham WB, Stary-Weinzinger A, Beyl S, Hering S, van den Berg DJ, de Lange ECM, Heitman LH, IJzerman AP, Vos MA, van der Heyden MAG. LUF7244, an allosteric modulator/activator of K v 11.1 channels, counteracts dofetilide-induced torsades de pointes arrhythmia in the chronic atrioventricular block dog model. Br J Pharmacol 2019; 176:3871-3885. [PMID: 31339551 PMCID: PMC6780032 DOI: 10.1111/bph.14798] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 07/08/2019] [Accepted: 07/11/2019] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND AND PURPOSE Kv 11.1 (hERG) channel blockade is an adverse effect of many drugs and lead compounds, associated with lethal cardiac arrhythmias. LUF7244 is a negative allosteric modulator/activator of Kv 11.1 channels that inhibits early afterdepolarizations in vitro. We tested LUF7244 for antiarrhythmic efficacy and potential proarrhythmia in a dog model. EXPERIMENTAL APPROACH LUF7244 was tested in vitro for (a) increasing human IKv11.1 and canine IKr and (b) decreasing dofetilide-induced action potential lengthening and early afterdepolarizations in cardiomyocytes derived from human induced pluripotent stem cells and canine isolated ventricular cardiomyocytes. In vivo, LUF7244 was given intravenously to anaesthetized dogs in sinus rhythm or with chronic atrioventricular block. KEY RESULTS LUF7244 (0.5-10 μM) concentration dependently increased IKv11.1 by inhibiting inactivation. In vitro, LUF7244 (10 μM) had no effects on IKIR2.1 , INav1.5 , ICa-L , and IKs , doubled IKr , shortened human and canine action potential duration by approximately 50%, and inhibited dofetilide-induced early afterdepolarizations. LUF7244 (2.5 mg·kg-1 ·15 min-1 ) in dogs with sinus rhythm was not proarrhythmic and shortened, non-significantly, repolarization parameters (QTc: -6.8%). In dogs with chronic atrioventricular block, LUF7244 prevented dofetilide-induced torsades de pointes arrhythmias in 5/7 animals without normalization of the QTc. Peak LUF7244 plasma levels were 1.75 ± 0.80 during sinus rhythm and 2.34 ± 1.57 μM after chronic atrioventricular block. CONCLUSIONS AND IMPLICATIONS LUF7244 counteracted dofetilide-induced early afterdepolarizations in vitro and torsades de pointes in vivo. Allosteric modulators/activators of Kv 11.1 channels might neutralize adverse cardiac effects of existing drugs and newly developed compounds that display QTc lengthening.
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Affiliation(s)
- Muge Qile
- Department of Medical Physiology, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Henriette D M Beekman
- Department of Medical Physiology, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - David J Sprenkeler
- Department of Medical Physiology, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Marien J C Houtman
- Department of Medical Physiology, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Willem B van Ham
- Department of Medical Physiology, University Medical Centre Utrecht, Utrecht, The Netherlands.,Department of Pharmacology and Toxicology, University of Vienna, Vienna, Austria
| | | | - Stanislav Beyl
- Department of Pharmacology and Toxicology, University of Vienna, Vienna, Austria
| | - Steffen Hering
- Department of Pharmacology and Toxicology, University of Vienna, Vienna, Austria
| | - Dirk-Jan van den Berg
- Division of Systems Biomedicine and Pharmacology, Leiden Academic Centre for Drug Research, Leiden University, Leiden, The Netherlands
| | - Elizabeth C M de Lange
- Division of Systems Biomedicine and Pharmacology, Leiden Academic Centre for Drug Research, Leiden University, Leiden, The Netherlands
| | - Laura H Heitman
- Division of Drug Discovery and Safety, Leiden Academic Centre for Drug Research, Leiden University, Leiden, The Netherlands
| | - Ad P IJzerman
- Division of Drug Discovery and Safety, Leiden Academic Centre for Drug Research, Leiden University, Leiden, The Netherlands
| | - Marc A Vos
- Department of Medical Physiology, University Medical Centre Utrecht, Utrecht, The Netherlands
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19
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Maessen GC, Wijnhoven AM, Neijzen RL, Paulus MC, van Heel DAM, Bomers BHA, Boersma LE, Konya B, van der Heyden MAG. Nicotine intoxication by e-cigarette liquids: a study of case reports and pathophysiology. Clin Toxicol (Phila) 2019; 58:1-8. [PMID: 31286797 DOI: 10.1080/15563650.2019.1636994] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Background: Electronic cigarettes (e-cigarettes), the smokeless alternative to conventional tobacco cigarettes, have become increasingly popular. E-cigarettes vaporise e-liquid, a solution of highly concentrated nicotine, propylene glycol (PG) and vegetable glycerine (VG). With the popularity of e-cigarettes, e-liquid refills have become easily accessible and several cases of intoxication due to the ingestion of e-liquid have been reported. We provide an overview of these cases, their pathophysiology and patients' characteristics.Methods: We carried out a retrospective evaluation of the scientific literature reporting on cases of liquid nicotine intoxication, using the following inclusion criteria: (1) the article is or contains a case report, (2) describes an intoxication with e-liquid, (3) the substance contains nicotine, and (4) intake is oral, intravenous or subcutaneous.Results: We found 26 case reports describing a total of 31 patients who suffered from e-liquid intoxication. All intoxications up to the age of six were reported as unintentional, whereas nearly all cases from ages 13 to 53 were due to suicide attempts. The three most prevalent symptoms of e-liquid intoxication were tachycardia, altered mental status and vomiting. Eleven cases resulted in the death of the patient. In the survivors, the highest plasma concentration of nicotine was 800 µg L-1, while the lowest concentration in the non-survivors was 1600 µg L-1.Conclusions: There is a mismatch between the generally accepted lethal oral nicotine dose of 60 mg, resulting in approximately 180 µg L-1 plasma concentration, and the 4.4- to 8.9-fold higher lethal plasma concentrations we found in cases of e-liquid intoxication. In these severe intoxications, plasma cotinine concentration does not act as a more reliable indicator of nicotine intoxication than nicotine itself. The ages of the patients display a bimodal distribution. In patients above the age of 10, intoxication results mainly from suicide attempts rather than accidental ingestion. The role of PG and VG in e-liquid intoxications is remarkably unclear. However, the similarity across nicotine and PG toxicity symptoms leads us to believe a cumulative effect cannot be excluded.
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Affiliation(s)
- Gerdinique C Maessen
- Honours Program CRU + Bachelor, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Anjali M Wijnhoven
- Honours Program CRU + Bachelor, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Rosalie L Neijzen
- Honours Program CRU + Bachelor, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Michelle C Paulus
- Honours Program CRU + Bachelor, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Dayna A M van Heel
- Honours Program CRU + Bachelor, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Bart H A Bomers
- Honours Program CRU + Bachelor, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Lucie E Boersma
- Honours Program CRU + Bachelor, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Burak Konya
- Honours Program CRU + Bachelor, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Marcel A G van der Heyden
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Utrecht, The Netherlands
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20
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Qile M, Ji Y, Houtman MJC, Veldhuis M, Romunde F, Kok B, van der Heyden MAG. Identification of a PEST Sequence in Vertebrate K IR2.1 That Modifies Rectification. Front Physiol 2019; 10:863. [PMID: 31333502 PMCID: PMC6624654 DOI: 10.3389/fphys.2019.00863] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Accepted: 06/20/2019] [Indexed: 11/13/2022] Open
Abstract
KIR2.1 potassium channels, producing inward rectifier potassium current (IK1), are important for final action potential repolarization and a stable resting membrane potential in excitable cells like cardiomyocytes. Abnormal KIR2.1 function, either decreased or increased, associates with diseases such as Andersen-Tawil syndrome, long and short QT syndromes. KIR2.1 ion channel protein trafficking and subcellular anchoring depends on intrinsic specific short amino acid sequences. We hypothesized that combining an evolutionary based sequence comparison and bioinformatics will identify new functional domains within the C-terminus of the KIR2.1 protein, which function could be determined by mutation analysis. We determined PEST domain signatures, rich in proline (P), glutamic acid (E), serine (S), and threonine (T), within KIR2.1 sequences using the “epestfind” webtool. WT and ΔPEST KIR2.1 channels were expressed in HEK293T and COS-7 cells. Patch-clamp electrophysiology measurements were performed in the inside-out mode on excised membrane patches and the whole cell mode using AxonPatch 200B amplifiers. KIR2.1 protein expression levels were determined by western blot analysis. Immunofluorescence microscopy was used to determine KIR2.1 subcellular localization. An evolutionary conserved PEST domain was identified in the C-terminus of the KIR2.1 channel protein displaying positive PEST scores in vertebrates ranging from fish to human. No similar PEST domain was detected in KIR2.2, KIR2.3, and KIR2.6 proteins. Deletion of the PEST domain in California kingsnake and human KIR2.1 proteins (ΔPEST), did not affect plasma membrane localization. Co-expression of WT and ΔPEST KIR2.1 proteins resulted in heterotetrameric channel formation. Deletion of the PEST domain did not increase protein stability in cycloheximide assays [T½ from 2.64 h (WT) to 1.67 h (ΔPEST), n.s.]. WT and ΔPEST channels, either from human or snake, produced typical IK1, however, human ΔPEST channels displayed stronger intrinsic rectification. The current observations suggest that the PEST sequence of KIR2.1 is not associated with rapid protein degradation, and has a role in the rectification behavior of IK1 channels.
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Affiliation(s)
- Muge Qile
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, Netherlands
| | - Yuan Ji
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, Netherlands
| | - Marien J C Houtman
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, Netherlands
| | - Marlieke Veldhuis
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, Netherlands
| | - Fee Romunde
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, Netherlands
| | - Bart Kok
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, Netherlands
| | - Marcel A G van der Heyden
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, Netherlands
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21
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Chen X, Garon A, Wieder M, Houtman MJC, Zangerl-Plessl EM, Langer T, van der Heyden MAG, Stary-Weinzinger A. Computational Identification of Novel Kir6 Channel Inhibitors. Front Pharmacol 2019; 10:549. [PMID: 31178728 PMCID: PMC6543810 DOI: 10.3389/fphar.2019.00549] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 05/01/2019] [Indexed: 12/25/2022] Open
Abstract
KATP channels consist of four Kir6.x pore-forming subunits and four regulatory sulfonylurea receptor (SUR) subunits. These channels couple the metabolic state of the cell to membrane excitability and play a key role in physiological processes such as insulin secretion in the pancreas, protection of cardiac muscle during ischemia and hypoxic vasodilation of arterial smooth muscle cells. Abnormal channel function resulting from inherited gain or loss-of-function mutations in either the Kir6.x and/or SUR subunits are associated with severe diseases such as neonatal diabetes, congenital hyperinsulinism, or Cantú syndrome (CS). CS is an ultra-rare genetic autosomal dominant disorder, caused by dominant gain-of-function mutations in SUR2A or Kir6.1 subunits. No specific pharmacotherapeutic treatment options are currently available for CS. Kir6 specific inhibitors could be beneficial for the development of novel drug therapies for CS, particular for mutations, which lack high affinity for sulfonylurea inhibitor glibenclamide. By applying a combination of computational methods including atomistic MD simulations, free energy calculations and pharmacophore modeling, we identified several novel Kir6.1 inhibitors, which might be possible candidates for drug repurposing. The in silico predictions were confirmed using inside/out patch-clamp analysis. Importantly, Cantú mutation C166S in Kir6.2 (equivalent to C176S in Kir6.1) and S1020P in SUR2A, retained high affinity toward the novel inhibitors. Summarizing, the inhibitors identified in this study might provide a starting point toward developing novel therapies for Cantú disease.
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Affiliation(s)
- Xingyu Chen
- Department of Pharmacology and Toxicology, University of Vienna, Vienna, Austria
| | - Arthur Garon
- Department of Pharmaceutical Chemistry, University of Vienna, Vienna, Austria
| | - Marcus Wieder
- Department of Pharmaceutical Chemistry, University of Vienna, Vienna, Austria
| | - Marien J. C. Houtman
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, Netherlands
| | | | - Thierry Langer
- Department of Pharmaceutical Chemistry, University of Vienna, Vienna, Austria
| | - Marcel A. G. van der Heyden
- Department of Pharmacology and Toxicology, University of Vienna, Vienna, Austria
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, Netherlands
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22
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Houtman MJC, Chen X, Qile M, Duran K, van Haaften G, Stary-Weinzinger A, van der Heyden MAG. Glibenclamide and HMR1098 normalize Cantú syndrome-associated gain-of-function currents. J Cell Mol Med 2019; 23:4962-4969. [PMID: 31119887 PMCID: PMC7346732 DOI: 10.1111/jcmm.14329] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 03/13/2019] [Accepted: 03/25/2019] [Indexed: 12/15/2022] Open
Abstract
Cantú syndrome (CS) is caused by dominant gain-of-function mutation in ATP-dependent potassium channels. Cellular ATP concentrations regulate potassium current thereby coupling energy status with membrane excitability. No specific pharmacotherapeutic options are available to treat CS but IKATP channels are pharmaceutical targets in type II diabetes or cardiac arrhythmia treatment. We have been suggested that IKATP inhibitors, glibenclamide and HMR1098, normalize CS channels. IKATP in response to Mg-ATP, glibenclamide and HMR1098 were measured by inside-out patch-clamp electrophysiology. Results were interpreted in view of cryo-EM IKATP channel structures. Mg-ATP IC50 values of outward current were increased for D207E (0.71 ± 0.14 mmol/L), S1020P (1.83 ± 0.10), S1054Y (0.95 ± 0.06) and R1154Q (0.75 ± 0.13) channels compared to H60Y (0.14 ± 0.01) and wild-type (0.15 ± 0.01). HMR1098 dose-dependently inhibited S1020P and S1054Y channels in the presence of 0.15 mmol/L Mg-ATP, reaching, at 30 μmol/L, current levels displayed by wild-type and H60Y channels in the presence of 0.15 mmol/L Mg-ATP. Glibenclamide (10 μmol/L) induced similar normalization. S1054Y sensitivity to glibenclamide increases strongly at 0.5 mmol/L Mg-ATP compared to 0.15 mmol/L, in contrast to D207E and S1020P channels. Experimental findings agree with structural considerations. We conclude that CS channel activity can be normalized by existing drugs; however, complete normalization can be achieved at supraclinical concentrations only.
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Affiliation(s)
- Marien J C Houtman
- Division of Heart and Lungs, Department of Medical Physiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Xingyu Chen
- Department of Pharmacology and Toxicology, University of Vienna, Vienna, Austria
| | - Muge Qile
- Division of Heart and Lungs, Department of Medical Physiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Karen Duran
- Center for Molecular Medicine, Department of Medical Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Gijs van Haaften
- Center for Molecular Medicine, Department of Medical Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | | | - Marcel A G van der Heyden
- Division of Heart and Lungs, Department of Medical Physiology, University Medical Center Utrecht, Utrecht, The Netherlands
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23
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van der Heyden MAG, Vos MA. Sex hormones and jumping heart beats. J Cardiovasc Electrophysiol 2019; 30:950-951. [PMID: 31006915 DOI: 10.1111/jce.13939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 04/01/2019] [Indexed: 11/28/2022]
Affiliation(s)
- Marcel A G van der Heyden
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Marc A Vos
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Utrecht, The Netherlands
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24
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Żołek T, Qile M, Kaźmierczak P, Bloothooft M, van der Heyden MAG, Maciejewska D. Drug-likeness of linear pentamidine analogues and their impact on the hERG K+channel – correlation with structural features. RSC Adv 2019; 9:38355-38371. [PMID: 35540224 PMCID: PMC9082326 DOI: 10.1039/c9ra08404e] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Accepted: 11/15/2019] [Indexed: 01/08/2023] Open
Abstract
The pentamidines with S atoms or sulfanilide groups in the linker have favorable drug-likeness parameters and low toxicity.
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Affiliation(s)
- Teresa Żołek
- Department of Organic Chemistry
- Faculty of Pharmacy
- Medical University of Warsaw
- 02-097 Warsaw
- Poland
| | - Muge Qile
- Department of Medical Physiology
- Division Heart & Lungs
- University Medical Center Utrecht
- Utrecht
- The Netherlands
| | - Paweł Kaźmierczak
- Department of Organic Chemistry
- Faculty of Pharmacy
- Medical University of Warsaw
- 02-097 Warsaw
- Poland
| | - Meye Bloothooft
- Department of Medical Physiology
- Division Heart & Lungs
- University Medical Center Utrecht
- Utrecht
- The Netherlands
| | - Marcel A. G. van der Heyden
- Department of Medical Physiology
- Division Heart & Lungs
- University Medical Center Utrecht
- Utrecht
- The Netherlands
| | - Dorota Maciejewska
- Department of Organic Chemistry
- Faculty of Pharmacy
- Medical University of Warsaw
- 02-097 Warsaw
- Poland
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25
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Zangerl-Plessl EM, van der Heyden MAG. Commentary: Golgin-97 Targets Ectopically Expressed Inward Rectifying Potassium Channel, Kir2.1, to the Trans-Golgi Network in COS-7 Cells. Front Physiol 2018; 9:1401. [PMID: 30344494 PMCID: PMC6182076 DOI: 10.3389/fphys.2018.01401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 09/14/2018] [Indexed: 11/30/2022] Open
Affiliation(s)
| | - Marcel A G van der Heyden
- Department of Pharmacology and Toxicology, University of Vienna, Vienna, Austria.,Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, Netherlands
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26
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van der Heyden MAG, Delisle BP, Abriel H. Editorial: Ion Channel Trafficking and Cardiac Arrhythmias. Front Physiol 2018; 9:1254. [PMID: 30319434 PMCID: PMC6167604 DOI: 10.3389/fphys.2018.01254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 08/20/2018] [Indexed: 11/13/2022] Open
Affiliation(s)
- Marcel A G van der Heyden
- Division of Heart and Lungs, Department of Medical Physiology, University Medical Center Utrecht, Utrecht, Netherlands
| | - Brian P Delisle
- Department of Physiology, University of Kentucky, Lexington, KY, United States
| | - Hugues Abriel
- Institute of Biochemistry and Molecular Medicine, Swiss National Centre of Competence in Research TransCure, University of Bern, Bern, Switzerland
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27
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Szatmári V, Ji Y, Herwijnen BV, Feng M, Wang MZ, Bossu A, van der Heyden MAG. Efficacy of pentamidine analogue 6 in dogs with chronic atrial fibrillation. J Vet Intern Med 2018; 32:1549-1554. [PMID: 30079486 PMCID: PMC6189345 DOI: 10.1111/jvim.15242] [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: 01/23/2018] [Revised: 04/25/2018] [Accepted: 05/21/2018] [Indexed: 01/13/2023] Open
Abstract
Background The inward rectifier inhibitor pentamidine analogue 6 (PA‐6) is effective in cardioversion of goats with persistent rapid pacing induced atrial fibrillation (AF) and is not proarrhythmic in dogs with experimental chronic 3rd‐degree AV block. Efficacy and safety in the clinical setting are unknown. Hypothesis That PA‐6 would be effective in converting AF to sinus rhythm (SR) in dogs with naturally occurring AF, without the presence of overt adverse effects. Animals Ten client‐owned large and giant breed dogs. Methods Animals with persistent or permanent AF were recruited for our prospective study. PA‐6 was administered IV as a bolus of 2.5 mg/kg 10 min−1 followed by a maintenance infusion of 0.04 mg/kg min−1 for a maximum of 50 minutes in conscious dogs. Standard 6 lead limb ECG was recorded during the infusion. Visible and audible signs of adverse effects were scored during the entire procedure. Results PA‐6 did not induce changes in QRS duration (54.7 ± 4.6 versus 56.7 ± 6.1 ms, P = .42), QTc interval (241.1 ± 19.5 versus 258.7 ± 19.8 ms, P = .061) or RR interval (363.4 ± 84.6 versus 440.8 ± 96.3 ms, P = .072) at the end of the bolus. No cardioversion to SR was observed in any dog. Three dogs displayed no adverse effects. Five dogs had premature ventricular depolarizations during PA‐6 infusion on the ECG. Respiratory distress with laryngeal stridor, subtle muscle twitching, and mild generalized muscular weakness were noncardiac adverse effects observed in 5 dogs. Adverse effects resolved spontaneously. Conclusions and Clinical importance Chronic naturally occurring AF in large and giant breed dogs could not be cardioverted to SR by PA‐6.
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Affiliation(s)
- Viktor Szatmári
- Department of Clinical Sciences of Companion Animals, Utrecht University, Utrecht, The Netherlands
| | - Yuan Ji
- Department of Medical Physiology, University Medical Center Utrecht, Utrecht, The Netherlands.,Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Bianca van Herwijnen
- Department of Medical Physiology, University Medical Center Utrecht, Utrecht, The Netherlands.,Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Mei Feng
- Department of Pharmaceutical Chemistry, School of Pharmacy, The University of Kansas, Lawrence, Kansas
| | - Michael Zhou Wang
- Department of Pharmaceutical Chemistry, School of Pharmacy, The University of Kansas, Lawrence, Kansas
| | - Alexandre Bossu
- Department of Medical Physiology, University Medical Center Utrecht, Utrecht, The Netherlands.,Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Marcel A G van der Heyden
- Department of Medical Physiology, University Medical Center Utrecht, Utrecht, The Netherlands.,Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, The Netherlands
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Bossu A, Kostense A, Beekman HDM, Houtman MJC, van der Heyden MAG, Vos MA. Istaroxime, a positive inotropic agent devoid of proarrhythmic properties in sensitive chronic atrioventricular block dogs. Pharmacol Res 2018; 133:132-140. [PMID: 29753687 DOI: 10.1016/j.phrs.2018.05.001] [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] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 04/25/2018] [Accepted: 05/01/2018] [Indexed: 02/07/2023]
Abstract
Current inotropic agents in heart failure therapy associate with low benefit and significant adverse effects, including ventricular arrhythmias. Istaroxime, a novel Na+/K+-transporting ATPase inhibitor, also stimulates SERCA2a activity, which would confer improved inotropic and lusitropic properties with less proarrhythmic effects. We investigated hemodynamic, electrophysiological and potential proarrhythmic and antiarrhythmic effects of istaroxime in control and chronic atrioventricular block (CAVB) dogs sensitive to drug-induced Torsades de Pointes arrhythmias (TdP). In isolated normal canine ventricular cardiomyocytes, istaroxime (0.3-10 μM) evoked no afterdepolarizations and significantly shortened action potential duration (APD) at 3 and 10 μM. Istaroxime at 3 μg/kg/min significantly increased left ventricular (LV) contractility (dP/dt+) and relaxation (dP/dt-) respectively by 81 and 94% in anesthetized control dogs (n = 6) and by 61 and 49% in anesthetized CAVB dogs (n = 7) sensitive to dofetilide-induced TdP. While istaroxime induced no ventricular arrhythmias in control conditions, only single ectopic beats occurred in 2/7 CAVB dogs, which were preceded by increase of short-term variability of repolarization (STV) and T wave alternans in LV unipolar electrograms. Istaroxime pre-treatment (3 μg/kg/min for 60 min) did not alleviate dofetilide-induced increase in repolarization and STV, and mildly reduced incidence of TdP from 6/6 to 4/6 CAVB dogs. In six CAVB dogs with dofetilide-induced TdP, administration of istaroxime (90 μg/kg/5 min) suppressed arrhythmic episodes in two animals. Taken together, inotropic and lusitropic properties of istaroxime in CAVB dogs were devoid of significant proarrhythmic effects in sensitive CAVB dogs, and istaroxime provides a moderate antiarrhythmic efficacy in prevention and suppression of dofetilide-induced TdP.
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Affiliation(s)
- Alexandre Bossu
- Department of Medical Physiology, Division Heart & Lungs, University Medical Center Utrecht, Utrecht, The Netherlands.
| | - Amée Kostense
- Department of Medical Physiology, Division Heart & Lungs, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Henriette D M Beekman
- Department of Medical Physiology, Division Heart & Lungs, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Marien J C Houtman
- Department of Medical Physiology, Division Heart & Lungs, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Marcel A G van der Heyden
- Department of Medical Physiology, Division Heart & Lungs, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Marc A Vos
- Department of Medical Physiology, Division Heart & Lungs, University Medical Center Utrecht, Utrecht, The Netherlands
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Bossu A, Houtman MJC, Meijborg VMF, Varkevisser R, Beekman HDM, Dunnink A, de Bakker JMT, Mollova N, Rajamani S, Belardinelli L, van der Heyden MAG, Vos MA. Selective late sodium current inhibitor GS-458967 suppresses Torsades de Pointes by mostly affecting perpetuation but not initiation of the arrhythmia. Br J Pharmacol 2018; 175:2470-2482. [PMID: 29582428 PMCID: PMC5980463 DOI: 10.1111/bph.14217] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 02/27/2018] [Accepted: 03/02/2018] [Indexed: 12/19/2022] Open
Abstract
Background and Purpose Enhanced late sodium current (late INa) in heart failure and long QT syndrome type 3 is proarrhythmic. This study investigated the antiarrhythmic effect and mode of action of the selective and potent late INa inhibitor GS‐458967 (GS967) against Torsades de Pointes arrhythmias (TdP) in the chronic atrioventricular block (CAVB) dog. Experimental Approach Electrophysiological and antiarrhythmic effects of GS967 were evaluated in isolated canine ventricular cardiomyocytes and CAVB dogs with dofetilide‐induced early afterdepolarizations (EADs) and TdP, respectively. Mapping of intramural cardiac electrical activity in vivo was conducted to study effects of GS967 on spatial dispersion of repolarization. Key Results GS967 (IC50~200nM) significantly shortened repolarization in canine ventricular cardiomyocytes and sinus rhythm (SR) dogs, in a concentration and dose‐dependent manner. In vitro, despite addition of 1μM GS967, dofetilide‐induced EADs remained present in 42% and 35% of cardiomyocytes from SR and CAVB dogs, respectively. Nonetheless, GS967 (787±265nM) completely abolished dofetilide‐induced TdP in CAVB dogs (10/14 after dofetilide to 0/14 dogs after GS967), while single ectopic beats (sEB) persisted in 9 animals. In vivo mapping experiments showed that GS967 significantly reduced spatial dispersion of repolarization: cubic dispersion was significantly decreased from 237±54ms after dofetilide to 123±34ms after GS967. Conclusion and Implications GS967 terminated all dofetilide‐induced TdP without completely suppressing EADs and sEB in vitro and in vivo, respectively. The antiarrhythmic mode of action of GS967, through the reduction of spatial dispersion of repolarization, seems to predominantly impede the perpetuation of arrhythmic events into TdP rather than their initiating trigger.
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Affiliation(s)
- Alexandre Bossu
- Department of Medical Physiology, Division Heart & Lungs, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Marien J C Houtman
- Department of Medical Physiology, Division Heart & Lungs, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Veronique M F Meijborg
- Department of Experimental Cardiology, Amsterdam Medical Center, Amsterdam, The Netherlands
| | - Rosanne Varkevisser
- Department of Medical Physiology, Division Heart & Lungs, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Henriette D M Beekman
- Department of Medical Physiology, Division Heart & Lungs, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Albert Dunnink
- Department of Medical Physiology, Division Heart & Lungs, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Jacques M T de Bakker
- Department of Medical Physiology, Division Heart & Lungs, University Medical Center Utrecht, Utrecht, The Netherlands.,Department of Experimental Cardiology, Amsterdam Medical Center, Amsterdam, The Netherlands
| | | | | | | | - Marcel A G van der Heyden
- Department of Medical Physiology, Division Heart & Lungs, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Marc A Vos
- Department of Medical Physiology, Division Heart & Lungs, University Medical Center Utrecht, Utrecht, The Netherlands
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30
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Te Dorsthorst RPM, Hendrikse J, Vervoorn MT, van Weperen VYH, van der Heyden MAG. Review of case reports on hyperkalemia induced by dietary intake: not restricted to chronic kidney disease patients. Eur J Clin Nutr 2018; 73:38-45. [PMID: 29588531 DOI: 10.1038/s41430-018-0154-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 02/19/2018] [Accepted: 02/28/2018] [Indexed: 12/31/2022]
Abstract
Hyperkalemia is a metabolic disturbance of the potassium balance that can cause potentially fatal cardiac arrhythmias. Kidney dysfunction and renin-angiotensin-aldosterone system inhibiting drugs are notorious for their tendency to induce hyperkalemia by decreasing the excretion of potassium. The role of dietary potassium intake in inducing hyperkalemia is less clear. We review and analyze the common presentation, laboratory, and electrocardiogram (ECG) findings and therapeutic options associated with dietary-induced hyperkalemia, and find evidence for hyperkalemia development in non-renal impaired patients. Thirty-five case reports including 44 incidences of oral intake-induced hyperkalemia were assessed, 17 patients did not suffer from kidney dysfunction. Mean age was 49 ± 20 years. Mean potassium concentration was 8.2 ± 1.4 mEq/l, most frequently caused by abundant intake of fruit and vegetables (n = 17) or salt substitutes (n = 12). In patients with normal kidney function, intake of salt substitutes or supplements was the main cause of hyperkalemia. Main symptoms encompassed muscle weakness (29.5%), vomiting (20.4%), and dyspnea (15.9%). When ECGs were performed (n = 30), abnormalities were present in 86.7% of cases. Treatment involved administration of insulin (n = 22), sodium/calcium polystyrene sulfonate (n = 14), and/or calcium gluconate (n = 14). Forty patients fully recovered. Three, non-renal impaired, patients passed away. These results offer insight into the clinical aspects of dietary-induced hyperkalemia and suggest that the common assumption that dietary-induced hyperkalemia is a condition of renal impaired patients might be incorrect.
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Affiliation(s)
- Rogier P M Te Dorsthorst
- Participant in the Honours Program CRU2006 Bachelor, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
| | - Jytte Hendrikse
- Participant in the Honours Program CRU2006 Bachelor, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
| | - Mats T Vervoorn
- Participant in the Honours Program CRU2006 Bachelor, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
| | - Valerie Y H van Weperen
- Participant in the Honours Program CRU2006 Bachelor, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
| | - Marcel A G van der Heyden
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM, Utrecht, The Netherlands.
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31
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Baburin I, Varkevisser R, Schramm A, Saxena P, Beyl S, Szkokan P, Linder T, Stary-Weinzinger A, van der Heyden MAG, Houtman M, Takanari H, Jonsson M, Beekman JHD, Hamburger M, Vos MA, Hering S. Dehydroevodiamine and hortiamine, alkaloids from the traditional Chinese herbal drug Evodia rutaecarpa, are I Kr blockers with proarrhythmic effects in vitro and in vivo. Pharmacol Res 2018; 131:150-163. [PMID: 29477480 DOI: 10.1016/j.phrs.2018.02.024] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [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: 08/24/2017] [Revised: 02/09/2018] [Accepted: 02/20/2018] [Indexed: 11/26/2022]
Abstract
Evodiae fructus is a widely used herbal drug in traditional Chinese medicine. Evodia extract was found to inhibit hERG channels. The aim of the current study was to identify hERG inhibitors in Evodia extract and to investigate their potential proarrhythmic effects. Dehydroevodiamine (DHE) and hortiamine were identified as IKr (rapid delayed rectifier current) inhibitors in Evodia extract by HPLC-microfractionation and subsequent patch clamp studies on human embryonic kidney cells. DHE and hortiamine inhibited IKr with IC50s of 253.2±26.3nM and 144.8±35.1nM, respectively. In dog ventricular cardiomyocytes, DHE dose-dependently prolonged the action potential duration (APD). Early afterdepolarizations (EADs) were seen in 14, 67, 100, and 67% of cells after 0.01, 0.1, 1 and 10μM DHE, respectively. The proarrhythmic potential of DHE was evaluated in 8 anesthetized rabbits and in 8 chronic atrioventricular block (cAVB) dogs. In rabbits, DHE increased the QT interval significantly by 12±10% (0.05mg/kg/5min) and 60±26% (0.5mg/kg/5min), and induced Torsade de Pointes arrhythmias (TdP, 0.5mg/kg/5min) in 2 rabbits. In cAVB dogs, 0.33mg/kg/5min DHE increased QT duration by 48±10% (P<0.05*) and induced TdP in 2/4 dogs. A higher dose did not induce TdP. In human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs), methanolic extracts of Evodia, DHE and hortiamine dose-dependently prolonged APD. At 3μM DHE and hortiamine induced EADs. hERG inhibition at submicromolar concentrations, APD prolongation and EADs in hiPSC-CMs and dose-dependent proarrhythmic effects of DHE at micromolar plasma concentrations in cAVB dogs should increase awareness regarding proarrhythmic effects of widely used Evodia extracts.
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Affiliation(s)
- Igor Baburin
- Department of Pharmacology and Toxicology, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria.
| | - Rosanne Varkevisser
- Department of Medical Physiology, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
| | - Anja Schramm
- Division of Pharmaceutical Biology, University of Basel, Klingelbergstrasse 50, 4056 Basel, Switzerland
| | - Priyanka Saxena
- Department of Pharmacology and Toxicology, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria
| | - Stanislav Beyl
- Department of Pharmacology and Toxicology, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria
| | - Phillip Szkokan
- Department of Pharmacology and Toxicology, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria; ChanPharm GmbH, Leidesdorfgasse 14, Top 6, 1190 Vienna, Austria
| | - Tobias Linder
- Department of Pharmacology and Toxicology, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria
| | - Anna Stary-Weinzinger
- Department of Pharmacology and Toxicology, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria
| | - Marcel A G van der Heyden
- Department of Medical Physiology, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
| | - Marien Houtman
- Department of Medical Physiology, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
| | - Hiroki Takanari
- Department of Medical Physiology, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
| | - Malin Jonsson
- Department of Medical Physiology, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
| | - Jet H D Beekman
- Department of Medical Physiology, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
| | - Matthias Hamburger
- Division of Pharmaceutical Biology, University of Basel, Klingelbergstrasse 50, 4056 Basel, Switzerland
| | - Marc A Vos
- Department of Medical Physiology, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
| | - Steffen Hering
- Department of Pharmacology and Toxicology, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria
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Abstract
Degradation of cellular material by lysosomes is known as autophagy, and its main function is to maintain cellular homeostasis for growth, proliferation and survival of the cell. In recent years, research has focused on the characterization of autophagy pathways. Targeting of autophagy mediators has been described predominantly in cancer treatment, but also in neurological and cardiovascular diseases. Although the number of studies is still limited, there are indications that activity of autophagy pathways increases under arrhythmic conditions. Moreover, an increasing number of antiarrhythmic and non-cardiac drugs are found to affect autophagy pathways. We, therefore, suggest that future work should recognize the largely unaddressed effects of antiarrhythmic agents and other classes of drugs on autophagy pathway activation and inhibition.
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Affiliation(s)
- Joanne J A van Bavel
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, Netherlands
| | - Marc A Vos
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, Netherlands
| | - Marcel A G van der Heyden
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, Netherlands
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Affiliation(s)
- Hiroki Takanari
- Clinical Research Center for Diabetes, Tokushima University Hospital, 2-50-1 Kuramoto-cho, Tokushima 770-8503, Japan
| | - Magda S C Fontes
- Laboratory of Experimental Cardiology, Department of Cardiology, Heart Lung Center Leiden, Albinusdreef 2, 2300RC Leiden, The Netherlands and Division of Heart & Lungs, Department of Medical Physiology, University Medical Center Utrecht, Yalelaan 50, 3584CM Utrecht, The Netherlands
| | - Marcel A G van der Heyden
- Division of Heart & Lungs, Department of Medical Physiology, University Medical Center Utrecht, Yalelaan 50, 3584CM Utrecht, The Netherlands
| | - Marc A Vos
- Division of Heart & Lungs, Department of Medical Physiology, University Medical Center Utrecht, Yalelaan 50, 3584CM Utrecht, The Netherlands
| | - Toon A B van Veen
- Division of Heart & Lungs, Department of Medical Physiology, University Medical Center Utrecht, Yalelaan 50, 3584CM Utrecht, The Netherlands
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Aréchiga-Figueroa IA, Marmolejo-Murillo LG, Cui M, Delgado-Ramírez M, van der Heyden MAG, Sánchez-Chapula JA, Rodríguez-Menchaca AA. High-potency block of Kir4.1 channels by pentamidine: Molecular basis. Eur J Pharmacol 2017; 815:56-63. [PMID: 28993158 DOI: 10.1016/j.ejphar.2017.10.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [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: 06/10/2017] [Revised: 10/03/2017] [Accepted: 10/05/2017] [Indexed: 02/06/2023]
Abstract
Inward rectifier potassium (Kir) channels are expressed in almost all mammalian tissues and contribute to a wide range of physiological processes. Kir4.1 channel expression is found in the brain, inner ear, eye, and kidney. Loss-of-function mutations in the pore-forming Kir4.1 subunit cause an autosomal recessive disorder characterized by epilepsy, ataxia, sensorineural deafness and tubulopathy (SeSAME/EST syndrome). Despite its importance in physiological and pathological conditions, pharmacological research of Kir4.1 is limited. Here, we characterized the effect of pentamidine on Kir4.1 channels using electrophysiology, mutagenesis and computational methods. Pentamidine potently inhibited Kir4.1 channels when applied to the cytoplasmic side under inside-out patch clamp configuration (IC50 = 97nM). The block was voltage dependent. Molecular modeling predicted the binding of pentamidine to the transmembrane pore region of Kir4.1 at aminoacids T127, T128 and E158. Mutation of each of these residues reduced the potency of pentamidine to block Kir4.1 channels. A pentamidine analog (PA-6) inhibited Kir4.1 with similar potency (IC50 = 132nM). Overall, this study shows that pentamidine blocks Kir4.1 channels interacting with threonine and glutamate residues in the transmembrane pore region. These results can be useful to design novel compounds with major potency and specificity over Kir4.1 channels.
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Affiliation(s)
- Iván A Aréchiga-Figueroa
- CONACYT, Facultad de Medicina, Universidad Autónoma de San Luis Potosí, San Luis Potosí, SLP, Mexico
| | | | - Meng Cui
- Department of Pharmaceutical Sciences, Northeastern University, Boston, MA, USA
| | - Mayra Delgado-Ramírez
- Departamento de Fisiología y Biofísica, Facultad de Medicina, Universidad Autónoma de San Luis Potosí, SLP, Mexico
| | - Marcel A G van der Heyden
- Department of Medical Physiology, Division Heart & Lungs, University Medical Center Utrecht, Utrecht, The Netherlands
| | - José A Sánchez-Chapula
- Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Colima, Col, Mexico
| | - Aldo A Rodríguez-Menchaca
- Departamento de Fisiología y Biofísica, Facultad de Medicina, Universidad Autónoma de San Luis Potosí, SLP, Mexico.
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Goversen B, van der Heyden MAG, van Veen TAB, de Boer TP. The immature electrophysiological phenotype of iPSC-CMs still hampers in vitro drug screening: Special focus on I K1. Pharmacol Ther 2017; 183:127-136. [PMID: 28986101 DOI: 10.1016/j.pharmthera.2017.10.001] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Preclinical drug screens are not based on human physiology, possibly complicating predictions on cardiotoxicity. Drug screening can be humanised with in vitro assays using human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs). However, in contrast to adult ventricular cardiomyocytes, iPSC-CMs beat spontaneously due to presence of the pacemaking current If and reduced densities of the hyperpolarising current IK1. In adult cardiomyocytes, IK1 finalises repolarisation by stabilising the resting membrane potential while also maintaining excitability. The reduced IK1 density contributes to proarrhythmic traits in iPSC-CMs, which leads to an electrophysiological phenotype that might bias drug responses. The proarrhythmic traits can be suppressed by increasing IK1 in a balanced manner. We systematically evaluated all studies that report strategies to mature iPSC-CMs and found that only few studies report IK1 current densities. Furthermore, these studies did not succeed in establishing sufficient IK1 levels as they either added too little or too much IK1. We conclude that reduced densities of IK1 remain a major flaw in iPSC-CMs, which hampers their use for in vitro drug screening.
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Affiliation(s)
- Birgit Goversen
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM, Utrecht, The Netherlands
| | - Marcel A G van der Heyden
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM, Utrecht, The Netherlands
| | - Toon A B van Veen
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM, Utrecht, The Netherlands
| | - Teun P de Boer
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM, Utrecht, The Netherlands.
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Ji Y, Veldhuis MG, Zandvoort J, Romunde FL, Houtman MJC, Duran K, van Haaften G, Zangerl-Plessl EM, Takanari H, Stary-Weinzinger A, van der Heyden MAG. PA-6 inhibits inward rectifier currents carried by V93I and D172N gain-of-function K IR2.1 channels, but increases channel protein expression. J Biomed Sci 2017; 24:44. [PMID: 28711067 PMCID: PMC5513211 DOI: 10.1186/s12929-017-0352-x] [Citation(s) in RCA: 12] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Accepted: 07/11/2017] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND The inward rectifier potassium current IK1 contributes to a stable resting membrane potential and phase 3 repolarization of the cardiac action potential. KCNJ2 gain-of-function mutations V93I and D172N associate with increased IK1, short QT syndrome type 3 and congenital atrial fibrillation. Pentamidine-Analogue 6 (PA-6) is an efficient (IC50 = 14 nM with inside-out patch clamp methodology) and specific IK1 inhibitor that interacts with the cytoplasmic pore region of the KIR2.1 ion channel, encoded by KCNJ2. At 10 μM, PA-6 increases wild-type (WT) KIR2.1 expression in HEK293T cells upon chronic treatment. We hypothesized that PA-6 will interact with and inhibit V93I and D172N KIR2.1 channels, whereas impact on channel expression at the plasma membrane requires higher concentrations. METHODS Molecular modelling was performed with the human KIR2.1 closed state homology model using FlexX. WT and mutant KIR2.1 channels were expressed in HEK293 cells. Patch-clamp single cell electrophysiology measurements were performed in the whole cell and inside-out mode of the patch clamp method. KIR2.1 expression level and localization were determined by western blot analysis and immunofluorescence microscopy, respectively. RESULTS PA-6 docking in the V93I/D172N double mutant homology model of KIR2.1 demonstrated that mutations and drug-binding site are >30 Å apart. PA-6 inhibited WT and V93I outward currents with similar potency (IC50 = 35.5 and 43.6 nM at +50 mV for WT and V93I), whereas D172N currents were less sensitive (IC50 = 128.9 nM at +50 mV) using inside-out patch-clamp electrophysiology. In whole cell mode, 1 μM of PA-6 inhibited outward IK1 at -50 mV by 28 ± 36%, 18 ± 20% and 10 ± 6%, for WT, V93I and D172N channels respectively. Western blot analysis demonstrated that PA-6 (5 μM, 24 h) increased KIR2.1 expression levels of WT (6.3 ± 1.5 fold), and V93I (3.9 ± 0.9) and D172N (4.8 ± 2.0) mutants. Immunofluorescent microscopy demonstrated dose-dependent intracellular KIR2.1 accumulation following chronic PA-6 application (24 h, 1 and 5 μM). CONCLUSIONS 1) KCNJ2 gain-of-function mutations V93I and D172N in the KIR2.1 ion channel do not impair PA-6 mediated inhibition of IK1, 2) PA-6 elevates KIR2.1 protein expression and induces intracellular KIR2.1 accumulation, 3) PA-6 is a strong candidate for further preclinical evaluation in treatment of congenital SQT3 and AF.
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Affiliation(s)
- Yuan Ji
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
| | - Marlieke G. Veldhuis
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
| | - Jantien Zandvoort
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
| | - Fee L. Romunde
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
| | - Marien J. C. Houtman
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
| | - Karen Duran
- Center for Molecular Medicine, Department of Medical Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Gijs van Haaften
- Center for Molecular Medicine, Department of Medical Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | | | - Hiroki Takanari
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
| | | | - Marcel A. G. van der Heyden
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
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Ji Y, Varkevisser R, Opacic D, Bossu A, Kuiper M, Beekman JDM, Yang S, Khan AP, Dobrev D, Voigt N, Wang MZ, Verheule S, Vos MA, van der Heyden MAG. The inward rectifier current inhibitor PA-6 terminates atrial fibrillation and does not cause ventricular arrhythmias in goat and dog models. Br J Pharmacol 2017; 174:2576-2590. [PMID: 28542844 PMCID: PMC5513871 DOI: 10.1111/bph.13869] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 05/16/2017] [Accepted: 05/16/2017] [Indexed: 01/24/2023] Open
Abstract
Background and Purpose The density of the inward rectifier current (IK1) increases in atrial fibrillation (AF), shortening effective refractory period and thus promoting atrial re‐entry. The synthetic compound pentamidine analogue 6 (PA‐6) is a selective and potent IK1 inhibitor. We tested PA‐6 for anti‐AF efficacy and potential proarrhythmia, using established models in large animals. Experimental Approach PA‐6 was applied i.v. in anaesthetized goats with rapid pacing‐induced AF and anaesthetized dogs with chronic atrio‐ventricular (AV) block. Electrophysiological and pharmacological parameters were determined. Key Results PA‐6 (2.5 mg·kg−1·10 min−1) induced cardioversion to sinus rhythm (SR) in 5/6 goats and prolonged AF cycle length. AF complexity decreased significantly before cardioversion. PA‐6 accumulated in cardiac tissue with ratios between skeletal muscle : atrial muscle : ventricular muscle of approximately 1:8:21. In SR dogs, PA‐6 peak plasma levels 10 min post infusion were 5.5 ± 0.9 μM, PA‐6 did not induce significant prolongation of QTc and did not affect heart rate, PQ or QRS duration. In dogs with chronic AV block, PA‐6 did not affect QRS but lengthened QTc during the experiment, but not chronically. PA‐6 did not induce TdP arrhythmias in nine animals (0/9) in contrast to dofetilide (5/9). PA‐6 (200 nM) inhibited IK1, but not IK,ACh, in human isolated atrial cardiomyocytes. Conclusion and Implications PA‐6 restored SR in goats with persistent AF and, in dogs with chronic AV block, prolonged QT intervals, without inducing TdP arrhythmias. Our results demonstrate cardiac safety and good anti‐AF properties for PA‐6.
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Affiliation(s)
- Yuan Ji
- Department of Medical Physiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Rosanne Varkevisser
- Department of Medical Physiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Dragan Opacic
- Department of Physiology, Cardiovascular Research Institute Maastricht, Maastricht, The Netherlands
| | - Alexandre Bossu
- Department of Medical Physiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Marion Kuiper
- Department of Physiology, Cardiovascular Research Institute Maastricht, Maastricht, The Netherlands
| | - Jet D M Beekman
- Department of Medical Physiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Sihyung Yang
- Department of Pharmaceutical Chemistry, School of Pharmacy, The University of Kansas, Lawrence, KS, USA
| | - Azinwi Phina Khan
- Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen, Essen, Germany
| | - Dobromir Dobrev
- Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen, Essen, Germany
| | - Niels Voigt
- Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen, Essen, Germany.,Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Georg-August University Göttingen, Göttingen, Germany.,DZHK (German Centre for Cardiovascular Research), Göttingen, Germany
| | - Michael Zhuo Wang
- Department of Pharmaceutical Chemistry, School of Pharmacy, The University of Kansas, Lawrence, KS, USA
| | - Sander Verheule
- Department of Physiology, Cardiovascular Research Institute Maastricht, Maastricht, The Netherlands
| | - Marc A Vos
- Department of Medical Physiology, University Medical Center Utrecht, Utrecht, The Netherlands
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Bossu A, Varkevisser R, Beekman HDM, Houtman MJC, van der Heyden MAG, Vos MA. Short-term Variability of Repolarization Is Superior to Other Repolarization Parameters in the Evaluation of Diverse Antiarrhythmic Interventions in the Chronic Atrioventricular Block Dog. J Cardiovasc Pharmacol 2017; 69:398-407. [PMID: 28574954 PMCID: PMC5464753 DOI: 10.1097/fjc.0000000000000488] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Short-term variability (STV), to quantify beat-to-beat variability of repolarization, is a surrogate parameter that reliably identifies proarrhythmic risk in preclinical models. Examples include not only the use in the chronic atrioventricular block (CAVB) dog model whereby it was developed but also in vulnerable patients with heart failure or drug-induced long QT syndrome. In the CAVB dog model, STV can specifically distinguish between safe and unsafe drugs in proarrhythmic screening. Conversely, this dog model also offers the possibility to evaluate antiarrhythmic strategies in a setting of Torsades de Pointes (TdP) induction with a standard IKr inhibitor. The different antiarrhythmic interventions studied in suppression and prevention of drug-induced TdP in vivo in the CAVB dog model and in vitro in canine ventricular cardiomyocytes are described in this overview. We provide evidence that STV predicts the magnitude of antiarrhythmic effect against TdP better than other repolarization parameters in both suppression and prevention conditions. Moreover, suppression and prevention experiments revealed the same level of antiarrhythmic efficacy, whereas cellular experiments seem more sensitive in comparison with drug testing in vivo. Together, these observations suggest that STV could be used as a consistent indicator to rank efficacy of antiarrhythmic interventions in a number of conditions.
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Affiliation(s)
- Alexandre Bossu
- Department of Medical Physiology, Division Heart and Lungs, University Medical Center Utrecht, Utrecht, the Netherlands
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Ji Y, Takanari H, Qile M, Nalos L, Houtman MJC, Romunde FL, Heukers R, van Bergen En Henegouwen PMP, Vos MA, van der Heyden MAG. Class III antiarrhythmic drugs amiodarone and dronedarone impair K IR 2.1 backward trafficking. J Cell Mol Med 2017; 21:2514-2523. [PMID: 28425222 PMCID: PMC5618701 DOI: 10.1111/jcmm.13172] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [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: 11/23/2016] [Accepted: 02/24/2017] [Indexed: 01/16/2023] Open
Abstract
Drug‐induced ion channel trafficking disturbance can cause cardiac arrhythmias. The subcellular level at which drugs interfere in trafficking pathways is largely unknown. KIR2.1 inward rectifier channels, largely responsible for the cardiac inward rectifier current (IK1), are degraded in lysosomes. Amiodarone and dronedarone are class III antiarrhythmics. Chronic use of amiodarone, and to a lesser extent dronedarone, causes serious adverse effects to several organs and tissue types, including the heart. Both drugs have been described to interfere in the late‐endosome/lysosome system. Here we defined the potential interference in KIR2.1 backward trafficking by amiodarone and dronedarone. Both drugs inhibited IK1 in isolated rabbit ventricular cardiomyocytes at supraclinical doses only. In HK‐KWGF cells, both drugs dose‐ and time‐dependently increased KIR2.1 expression (2.0 ± 0.2‐fold with amiodarone: 10 μM, 24 hrs; 2.3 ± 0.3‐fold with dronedarone: 5 μM, 24 hrs) and late‐endosomal/lysosomal KIR2.1 accumulation. Increased KIR2.1 expression level was also observed in the presence of Nav1.5 co‐expression. Augmented KIR2.1 protein levels and intracellular accumulation were also observed in COS‐7, END‐2, MES‐1 and EPI‐7 cells. Both drugs had no effect on Kv11.1 ion channel protein expression levels. Finally, amiodarone (73.3 ± 10.3% P < 0.05 at −120 mV, 5 μM) enhanced IKIR2.1 upon 24‐hrs treatment, whereas dronedarone tended to increase IKIR2.1 and it did not reach significance (43.8 ± 5.5%, P = 0.26 at −120 mV; 2 μM). We conclude that chronic amiodarone, and potentially also dronedarone, treatment can result in enhanced IK1 by inhibiting KIR2.1 degradation.
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Affiliation(s)
- Yuan Ji
- Division of Heart & Lungs, Department of Medical Physiology, UMCU, Utrecht, The Netherlands
| | - Hiroki Takanari
- Division of Heart & Lungs, Department of Medical Physiology, UMCU, Utrecht, The Netherlands
| | - Muge Qile
- Division of Heart & Lungs, Department of Medical Physiology, UMCU, Utrecht, The Netherlands
| | - Lukas Nalos
- Department of Physiology, Faculty of Medicine in Pilsen, Charles University in Prague, Pilsen, Czech Republic
| | - Marien J C Houtman
- Division of Heart & Lungs, Department of Medical Physiology, UMCU, Utrecht, The Netherlands
| | - Fee L Romunde
- Division of Heart & Lungs, Department of Medical Physiology, UMCU, Utrecht, The Netherlands
| | - Raimond Heukers
- Cell Biology, Department of Biology, Science Faculty, Utrecht University, Utrecht, The Netherlands
| | | | - Marc A Vos
- Division of Heart & Lungs, Department of Medical Physiology, UMCU, Utrecht, The Netherlands
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El Idrissi A, van Berkel L, Bonekamp NE, Dalemans DJZ, van der Heyden MAG. The toxicology of zinc chloride smoke producing bombs and screens. Clin Toxicol (Phila) 2017; 55:167-174. [PMID: 28074704 DOI: 10.1080/15563650.2016.1271125] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
CONTEXT Zinc chloride (ZnCl2)-based smoke bombs and screens are in use since the Second World War (1939-1945). Many case descriptions on ZnCl2 smoke inhalation incidents appeared since 1945. OBJECTIVE We provide a comprehensive overview of the clinical symptoms and underlying pathophysiology due to exposure to fumes from ZnCl2 smoke producing bombs. In addition, we give a historical overview of treatment regimens and their outcomes. METHODOLOGY We performed a literature search on Medline, Scopus and Google Scholar databases using combinations of the following search terms "smoke bomb", "smoke screen", "ZnCl2", "intoxication", "poisoning", "case report", "HE smoke", "hexachloroethane smoke", "smoke inhalation" and "white smoke". We retrieved additional reports based on the primary hits. We collected 30 case reports from the last seven decades encompassing 376 patients, 23 of whom died. Of all the patient descriptions, 31 were of sufficient detail for prudent analysis. RESULTS AND CONCLUSIONS Intoxication with clinical signs mainly took place in war situations and in military and fire emergency training sessions in enclosed spaces. Symptoms follow a biphasic course mainly characterised by dyspnoea, coughing and lacrimation, related to irritation of the airways in the first six hours, followed by reappearance of early signs complemented with inflammation related signs and tachycardia from 24 h onwards. Acute respiratory stress syndrome developed in severely affected individuals. Chest radiographs did not always correspond with clinical symptoms. Common therapy comprises corticosteroids, antibiotics and supplemental oxygen or positive pressure ventilation in 64% of the cases. Of the 31 patients included, eight died, three had permanent lung damage and 15 showed complete recovery, whereas in five patients outcome was not reported. Early signs likely relate to caustic reactions in the airway lining, whereas inhaled ZnCl2 particles may trigger an inflammatory response and associated delayed fibrotic lung damage. Smoke bomb poisoning is a potentially lethal condition that can occur in large cohorts of victims simultaneously.
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Affiliation(s)
- Ayman El Idrissi
- a Honours Program CRU2006 Bachelor, University Medical Center Utrecht , Utrecht , The Netherlands
| | - Lisanne van Berkel
- a Honours Program CRU2006 Bachelor, University Medical Center Utrecht , Utrecht , The Netherlands
| | - Nadia E Bonekamp
- a Honours Program CRU2006 Bachelor, University Medical Center Utrecht , Utrecht , The Netherlands
| | - Diana J Z Dalemans
- a Honours Program CRU2006 Bachelor, University Medical Center Utrecht , Utrecht , The Netherlands
| | - Marcel A G van der Heyden
- b Department of Medical Physiology, Division of Heart & Lungs , University Medical Center Utrecht , Utrecht , The Netherlands
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Goversen B, de Boer TP, van der Heyden MAG. Commentary: Reciprocal Modulation of I K1-I Na Extends Excitability in Cardiac Ventricular Cells. Front Physiol 2016; 7:647. [PMID: 28066270 PMCID: PMC5179521 DOI: 10.3389/fphys.2016.00647] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 12/09/2016] [Indexed: 12/30/2022] Open
Affiliation(s)
- Birgit Goversen
- Division of Heart and Lungs, Department of Medical Physiology, University Medical Center Utrecht Utrecht, Netherlands
| | - Teun P de Boer
- Division of Heart and Lungs, Department of Medical Physiology, University Medical Center Utrecht Utrecht, Netherlands
| | - Marcel A G van der Heyden
- Division of Heart and Lungs, Department of Medical Physiology, University Medical Center Utrecht Utrecht, Netherlands
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Takanari H, Bourgonje VJA, Fontes MSC, Raaijmakers AJA, Driessen H, Jansen JA, van der Nagel R, Kok B, van Stuijvenberg L, Boulaksil M, Takemoto Y, Yamazaki M, Tsuji Y, Honjo H, Kamiya K, Kodama I, Anderson ME, van der Heyden MAG, van Rijen HVM, van Veen TAB, Vos MA. Calmodulin/CaMKII inhibition improves intercellular communication and impulse propagation in the heart and is antiarrhythmic under conditions when fibrosis is absent. Cardiovasc Res 2016; 111:410-21. [PMID: 27357638 PMCID: PMC4996261 DOI: 10.1093/cvr/cvw173] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Revised: 06/09/2016] [Accepted: 06/21/2016] [Indexed: 11/14/2022] Open
Abstract
AIM In healthy hearts, ventricular gap junctions are mainly composed by connexin43 (Cx43) and localize in the intercalated disc, enabling appropriate electrical coupling. In diseased hearts, Cx43 is heterogeneously down-regulated, whereas activity of calmodulin/calcium-calmodulin protein kinase II (CaM/CaMKII) signalling increases. It is unclear if CaM/CaMKII affects Cx43 expression/localization or impulse propagation. We analysed different models to assess this. METHODS AND RESULTS AC3-I mice with CaMKII genetically inhibited were subjected to pressure overload (16 weeks, TAC vs. sham). Optical and epicardial mapping was performed on Langendorff-perfused rabbit and AC3-I hearts, respectively. Cx43 subcellular distribution from rabbit/mouse ventricles was evaluated by immunoblot after Triton X-100-based fractionation. In mice with constitutively reduced CaMKII activity (AC3-I), conduction velocity (CV) was augmented (n = 11, P < 0.01 vs. WT); in AC3-I, CV was preserved after TAC, in contrast to a reduction seen in TAC-WT mice (-20%). Cx43 expression was preserved after TAC in AC3-I mice, though arrhythmias and fibrosis were still present. In rabbits, W7 (CaM inhibitor, 10 µM) increased CV (6-13%, n= 6, P< 0.05), while susceptibility to arrhythmias decreased. Immunoconfocal microscopy revealed enlarged Cx43 cluster sizes at intercalated discs of those hearts. Total Cx43 did not change by W7 (n= 4), whereas Triton X-100 insoluble Cx43 increased (+21%, n= 4, P< 0.01). Similar findings were obtained in AC3-I mouse hearts when compared with control, and in cultured dog cardiomyocytes. Functional implication was shown through increased intercellular coupling in cultured neonatal rat cardiomyocytes. CONCLUSION Both acute and chronic CaM/CaMKII inhibition improves conduction characteristics and enhances localization of Cx43 in the intercalated disc. In the absence of fibrosis, this reduced the susceptibility for arrhythmias.
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Affiliation(s)
- Hiroki Takanari
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Utrecht, The Netherlands Department of Cardiovascular Research, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan Department of Pathophysiology, Oita University School of Medicine, Yufu, Japan
| | - Vincent J A Bourgonje
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Magda S C Fontes
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Antonia J A Raaijmakers
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Helen Driessen
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Utrecht, The Netherlands
| | - John A Jansen
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Roel van der Nagel
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Bart Kok
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Leonie van Stuijvenberg
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Mohamed Boulaksil
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Utrecht, The Netherlands Department of Cardiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Yoshio Takemoto
- Department of Cardiovascular Research, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan
| | - Masatoshi Yamazaki
- Department of Cardiovascular Research, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan
| | - Yukiomi Tsuji
- Department of Cardiovascular Research, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan
| | - Haruo Honjo
- Department of Cardiovascular Research, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan
| | - Kaichiro Kamiya
- Department of Cardiovascular Research, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan
| | | | - Mark E Anderson
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MA, USA
| | - Marcel A G van der Heyden
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Harold V M van Rijen
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Toon A B van Veen
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Marc A Vos
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Utrecht, The Netherlands
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43
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Yu Z, van Veldhoven JPD, Louvel J, ’t Hart IME, Rook MB, van der Heyden MAG, Heitman LH, IJzerman AP. Structure–Affinity Relationships (SARs) and Structure–Kinetics Relationships (SKRs) of Kv11.1 Blockers. J Med Chem 2015; 58:5916-29. [DOI: 10.1021/acs.jmedchem.5b00518] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Zhiyi Yu
- Division
of Medicinal Chemistry, Leiden Academic Centre for Drug Research, Leiden University, 2300 RA Leiden, The Netherlands
| | - Jacobus P. D. van Veldhoven
- Division
of Medicinal Chemistry, Leiden Academic Centre for Drug Research, Leiden University, 2300 RA Leiden, The Netherlands
| | - Julien Louvel
- Division
of Medicinal Chemistry, Leiden Academic Centre for Drug Research, Leiden University, 2300 RA Leiden, The Netherlands
| | - Ingrid M. E. ’t Hart
- Division
of Medicinal Chemistry, Leiden Academic Centre for Drug Research, Leiden University, 2300 RA Leiden, The Netherlands
| | - Martin B. Rook
- Department of Medical Physiology, Division Heart & Lungs, University Medical Centre Utrecht, 3584 CM Utrecht, The Netherlands
| | - Marcel A. G. van der Heyden
- Department of Medical Physiology, Division Heart & Lungs, University Medical Centre Utrecht, 3584 CM Utrecht, The Netherlands
| | - Laura H. Heitman
- Division
of Medicinal Chemistry, Leiden Academic Centre for Drug Research, Leiden University, 2300 RA Leiden, The Netherlands
| | - Adriaan P. IJzerman
- Division
of Medicinal Chemistry, Leiden Academic Centre for Drug Research, Leiden University, 2300 RA Leiden, The Netherlands
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44
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Burgers PP, van der Heyden MAG, Kok B, Heck AJR, Scholten A. A Systematic Evaluation of Protein Kinase A–A-Kinase Anchoring Protein Interaction Motifs. Biochemistry 2014; 54:11-21. [DOI: 10.1021/bi500721a] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Pepijn P. Burgers
- Biomolecular
Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular
Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
- Netherlands Proteomics Centre, Padualaan
8, 3584 CH Utrecht, The Netherlands
| | - Marcel A. G. van der Heyden
- Department
of Medical Physiology, Division of Heart and Lungs, University Medical Centre Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
| | - Bart Kok
- Department
of Medical Physiology, Division of Heart and Lungs, University Medical Centre Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
| | - Albert J. R. Heck
- Biomolecular
Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular
Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
- Netherlands Proteomics Centre, Padualaan
8, 3584 CH Utrecht, The Netherlands
| | - Arjen Scholten
- Biomolecular
Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular
Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
- Netherlands Proteomics Centre, Padualaan
8, 3584 CH Utrecht, The Netherlands
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Varkevisser R, van der Heyden MAG, Tieland RG, Beekman JDM, Vos MA. Vernakalant is devoid of proarrhythmic effects in the complete AV block dog model. Eur J Pharmacol 2013; 720:49-54. [PMID: 24211677 DOI: 10.1016/j.ejphar.2013.10.054] [Citation(s) in RCA: 11] [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] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Revised: 10/25/2013] [Accepted: 10/29/2013] [Indexed: 11/28/2022]
Abstract
The anesthetized chronic AV-blocked dog (cAVB) and methoxamine-sensitized rabbit model are widely used to determine pro-arrhythmic properties of drugs. In general, both models show similar results. However, conflicting data have also been reported; K201 and AZD1305 induced Torsade de Pointes (TdP) exclusively in cAVB dogs. Vernakalant, an antiarrhythmic drug that blocks several ion channels has been approved only in Europe. Its propensity to induce repolarization-dependent TdP arrhythmias has been evaluated solely in the methoxamine-sensitized rabbits. We therefore assessed the proarrhythmic potential of vernakalant in the cAVB dog model. Vernakalant was evaluated in 10 mongrel dogs (sinus rhythm (SR) 2mg/kg; chronic AV block (cAVB) 2+3mg/kg). The same dogs were challenged with dofetilide (25 μg/kg) to evaluate TdP inducibility. During the serial experiments the animals were paced from the right ventricular apex (60 beats/min). Short-term variability of repolarization (STV) was quantified for proarrhythmic risk. In SR (n=8) vernakalant prolonged QT (265 ± 11 to 311 ± 18 ms P<0.01(**)) but not PQ or QRS. In cAVB (n=8), 2mg/kg vernakalant prolonged QT (391 ± 43 to 519 ± 73 ms(**)) and QRS (103 ± 24 to 108 ± 23 ms(**)). After a 30 min lag-time, 3mg/kg vernakalant (n=4) increased QT to a lesser extent (413 ± 34 to 454 ± 27 ms(**)) while maintaining QRS prolongation (114 ± 18 to 122 ± 20 ms(**)). Neither dose increased STV or caused arrhythmias. Dofetilide prolonged QT (398 ± 51 to 615 ± 71 ms(**)), increased STV (1.0 ± 0.4 to 2.2 ± 1.0 ms P<0.05(⁎)) and induced TdP arrhythmias in 6/8(⁎) cAVB dogs. Vernakalant did not induce arrhythmias in the cAVB dog model. Higher dosages (3mg/kg) did not prolong repolarization further whereas negative inotropic effects were starting to become apparent precluding further increases in dose.
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Affiliation(s)
- Rosanne Varkevisser
- Department of Medical Physiology, Division Heart & Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
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Noorman M, Hakim S, Asimaki A, Vreeker A, van Rijen HVM, van der Heyden MAG, de Jonge N, de Weger RA, Hauer RNW, Saffitz JE, van Veen TAB. Reduced plakoglobin immunoreactivity in arrhythmogenic cardiomyopathy: methodological considerations. Cardiovasc Pathol 2013; 22:314-8. [PMID: 23688911 DOI: 10.1016/j.carpath.2013.04.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [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: 11/30/2012] [Revised: 04/03/2013] [Accepted: 04/06/2013] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND Arrhythmogenic cardiomyopathy (AC) primarily is considered to be a desmosomal disease with a predominant right ventricular phenotype. Reduced signal intensity for junctional plakoglobin (JUP) at the intercalated disks has been proposed as a marker that contributes to diagnosis of the disease. In this technical study, we investigated how methodology-related differences caused by tissue preservation and antibody dilutions affect an appropriate diagnosis. METHODS Autopsy and biopsy material was available from a total of 7 control and 25 AC patients that fulfilled the diagnostic Task Force Criteria as proposed in 2010. Immunohistochemical analysis was performed on cryosections and formalin-fixed material using antibodies against JUP and N-Cadherin. RESULTS Immunohistochemistry (1:1000 antibody dilution) on formalin-fixed material showed a reduced signal for JUP in 7/10 AC patients in a bidirectional, double-blinded exchange experiment in which 77% of individuals were correctly classified. Unmasking this disturbed JUP pattern was highly dependent on tissue preservation and antibody dilution since on cryosections the disturbed pattern in patients could only be unmasked at a very strong antibody dilution of 1:100000. CONCLUSIONS Reduced immunoreactive signal of JUP at the intercalated disks can be observed in a majority of AC patients. These changes can comparably be detected on both cryo- (74%) and formalin-fixed material (70%) but demand a different, highly defined, and uniformly used approach.
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Affiliation(s)
- Maartje Noorman
- Department of Medical Physiology, University Medical Center Utrecht, 3584CM Utrecht, The Netherlands; Interuniversity Cardiology Institute, The Netherlands
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Noorman M, Hakim S, Kessler E, Groeneweg JA, Cox MGPJ, Asimaki A, van Rijen HVM, van Stuijvenberg L, Chkourko H, van der Heyden MAG, Vos MA, de Jonge N, van der Smagt JJ, Dooijes D, Vink A, de Weger RA, Varro A, de Bakker JMT, Saffitz JE, Hund TJ, Mohler PJ, Delmar M, Hauer RNW, van Veen TAB. Remodeling of the cardiac sodium channel, connexin43, and plakoglobin at the intercalated disk in patients with arrhythmogenic cardiomyopathy. Heart Rhythm 2012. [PMID: 23178689 DOI: 10.1016/j.hrthm.2012.11.018] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
BACKGROUND Arrhythmogenic cardiomyopathy (AC) is closely associated with desmosomal mutations in a majority of patients. Arrhythmogenesis in patients with AC is likely related to remodeling of cardiac gap junctions and increased levels of fibrosis. Recently, using experimental models, we also identified sodium channel dysfunction secondary to desmosomal dysfunction. OBJECTIVE To assess the immunoreactive signal levels of the sodium channel protein NaV1.5, as well as connexin43 (Cx43) and plakoglobin (PKG), in myocardial specimens obtained from patients with AC. METHODS Left and right ventricular free wall postmortem material was obtained from 5 patients with AC and 5 controls matched for age and sex. Right ventricular septal biopsies were taken from another 15 patients with AC. All patients fulfilled the 2010 revised Task Force Criteria for the diagnosis of AC. Immunohistochemical analyses were performed using antibodies against Cx43, PKG, NaV1.5, plakophilin-2, and N-cadherin. RESULTS N-cadherin and desmoplakin immunoreactive signals and distribution were normal in patients with AC compared to controls. Plakophilin-2 signals were unaffected unless a plakophilin-2 mutation predicting haploinsufficiency was present. Distribution was unchanged compared to that in controls. Immunoreactive signal levels of PKG, Cx43, and NaV1.5 were disturbed in 74%, 70%, and 65% of the patients, respectively. CONCLUSIONS A reduced immunoreactive signal of PKG, Cx43, and NaV1.5 at the intercalated disks can be observed in a large majority of the patients. Decreased levels of Nav1.5 might contribute to arrhythmia vulnerability and, in the future, potentially could serve as a new clinically relevant tool for risk assessment strategies.
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Affiliation(s)
- Maartje Noorman
- Department of Medical Physiology, University Medical Center Utrecht, Utrecht, The Netherlands
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Burgers PP, Ma Y, Margarucci L, Mackey M, van der Heyden MAG, Ellisman M, Scholten A, Taylor SS, Heck AJR. A small novel A-kinase anchoring protein (AKAP) that localizes specifically protein kinase A-regulatory subunit I (PKA-RI) to the plasma membrane. J Biol Chem 2012; 287:43789-97. [PMID: 23115245 DOI: 10.1074/jbc.m112.395970] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Protein kinase A-anchoring proteins (AKAPs) provide spatio-temporal specificity for the omnipotent cAMP-dependent protein kinase (PKA) via high affinity interactions with PKA regulatory subunits (PKA-RI, RII). Many PKA-RII-AKAP complexes are heavily tethered to cellular substructures, whereas PKA-RI-AKAP complexes have remained largely undiscovered. Here, using a cAMP affinity-based chemical proteomics strategy in human heart and platelets, we uncovered a novel, ubiquitously expressed AKAP, termed small membrane (sm)AKAP due to its specific localization at the plasma membrane via potential myristoylation/palmitoylation anchors. In vitro binding studies revealed specificity of smAKAP for PKA-RI (K(d) = 7 nM) over PKA-RII (K(d) = 53 nM) subunits, co-expression of smAKAP with the four PKA R subunits revealed an even more exclusive specificity of smAKAP for PKA-RIα/β in the cellular context. Applying the singlet oxygen-generating electron microscopy probe miniSOG indicated that smAKAP is tethered to the plasma membrane and is particularly dense at cell-cell junctions and within filopodia. Our preliminary functional characterization of smAKAP provides evidence that, like PKA-RII, PKA-RI can be tightly tethered by a novel repertoire of AKAPs, providing a new perspective on spatio-temporal control of cAMP signaling.
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Affiliation(s)
- Pepijn P Burgers
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands
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Stams TRG, Bourgonje VJA, Vos MA, van der Heyden MAG. Verapamil as an antiarrhythmic agent in congestive heart failure: hopping from rabbit to human? Br J Pharmacol 2012; 166:554-6. [PMID: 22188337 DOI: 10.1111/j.1476-5381.2011.01818.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Repolarization-dependent cardiac arrhythmias only arise in hearts facing multiple 'challenges' affecting its so-called repolarization reserve. Congestive heart failure (CHF) is one such challenge frequently observed in humans and is accompanied by altered calcium handling within the contractile heart cell. This raises the question as to whether or not the well-known calcium channel antagonist verapamil acts as an antiarrhythmic drug in this setting, as seen in arrhythmia models without CHF. According to the study of Milberg et al. in this issue of BJP, the answer is yes. The results of this study, using a rabbit CHF model, raise important questions. First, given that the model combines CHF with a number of other interventions that predispose towards arrhythmia, will similar conclusions be reached in a setting where CHF is a more prominent proarrhythmic challenge; second, what is the extent to which other effects of calcium channel block would limit the clinical viability of this pharmacological approach in CHF? In vivo studies in large animal CHF models are now required to further explore this interesting, but complex, approach to the treatment of arrhythmia. LINKED ARTICLE This article is a commentary on Milberg et al., pp. 557-568 of this issue. To view this paper visit http://dx.doi.org/10.1111/j.1476-5381.2011.01721.x.
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Affiliation(s)
- Thom R G Stams
- Department of Medical Physiology, Division Heart & Lungs, University Medical Center Utrecht, Utrecht, The Netherlands
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50
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Abstract
Many plants of the Ericaceae family, Rhododendron, Pieris, Agarista and Kalmia, contain diterpene grayanotoxins. Consumption of grayanotoxin containing leaves, flowers or secondary products as honey may result in intoxication specifically characterized by dizziness, hypotension and atrial-ventricular block. Symptoms are caused by an inability to inactivate neural sodium ion channels resulting in continuous increased vagal tone. Grayanotoxin containing products are currently sold online, which may pose an increasing risk. In humans, intoxication is rarely lethal, in contrast to cattle and pet poisoning cases. Scientific evidence for the medicinal properties of grayanotoxin containing preparations, such as honey or herbal preparation in use in folk medicine, is scarce, and such use may even be harmful.
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Affiliation(s)
- Suze A. Jansen
- Honours Program CRU2006 Bachelor, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| | - Iris Kleerekooper
- Honours Program CRU2006 Bachelor, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| | - Zonne L. M. Hofman
- Honours Program CRU2006 Bachelor, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| | - Isabelle F. P. M. Kappen
- Honours Program CRU2006 Bachelor, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| | - Anna Stary-Weinzinger
- Department of Pharmacology and Toxicology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria
| | - Marcel A. G. van der Heyden
- Honours Program CRU2006 Bachelor, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
- Division of Heart and Lungs, Department of Medical Physiology, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
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