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Nagy N, Tóth N, Nánási PP. Antiarrhythmic and Inotropic Effects of Selective Na +/Ca 2+ Exchanger Inhibition: What Can We Learn from the Pharmacological Studies? Int J Mol Sci 2022; 23:ijms232314651. [PMID: 36498977 PMCID: PMC9736231 DOI: 10.3390/ijms232314651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 11/15/2022] [Accepted: 11/16/2022] [Indexed: 11/25/2022] Open
Abstract
Life-long stable heart function requires a critical balance of intracellular Ca2+. Several ion channels and pumps cooperate in a complex machinery that controls the influx, release, and efflux of Ca2+. Probably one of the most interesting and most complex players of this crosstalk is the Na+/Ca2+ exchanger, which represents the main Ca2+ efflux mechanism; however, under some circumstances, it can also bring Ca2+ into the cell. Therefore, the inhibition of the Na+/Ca2+ exchanger has emerged as one of the most promising possible pharmacological targets to increase Ca2+ levels, to decrease arrhythmogenic depolarizations, and to reduce excessive Ca2+ influx. In line with this, as a response to increasing demand, several more or less selective Na+/Ca2+ exchanger inhibitor compounds have been developed. In the past 20 years, several results have been published regarding the effect of Na+/Ca2+ exchanger inhibition under various circumstances, e.g., species, inhibitor compounds, and experimental conditions; however, the results are often controversial. Does selective Na+/Ca2+ exchanger inhibition have any future in clinical pharmacological practice? In this review, the experimental results of Na+/Ca2+ exchanger inhibition are summarized focusing on the data obtained by novel highly selective inhibitors.
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Affiliation(s)
- Norbert Nagy
- ELKH-SZTE Research Group of Cardiovascular Pharmacology, 6720 Szeged, Hungary
- Department of Pharmacology and Pharmacotherapy, Albert Szent-Györgyi Medical School, University of Szeged, 6720 Szeged, Hungary
- Correspondence: ; Tel.: +36-62-545-682; Fax: +36-62-545-680
| | - Noémi Tóth
- ELKH-SZTE Research Group of Cardiovascular Pharmacology, 6720 Szeged, Hungary
| | - Péter P. Nánási
- Department of Physiology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary
- Department of Dental Physiology and Pharmacology, Faculty of Dentistry, University of Debrecen, 4032 Debrecen, Hungary
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Ballarini E, Malacrida A, Rodriguez-Menendez V, Pozzi E, Canta A, Chiorazzi A, Monza L, Semperboni S, Meregalli C, Carozzi VA, Hashemi M, Nicolini G, Scuteri A, Housley SN, Cavaletti G, Alberti P. Sodium-Calcium Exchanger 2: A Pivotal Role in Oxaliplatin Induced Peripheral Neurotoxicity and Axonal Damage? Int J Mol Sci 2022; 23:10063. [PMID: 36077454 PMCID: PMC9456447 DOI: 10.3390/ijms231710063] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 08/26/2022] [Accepted: 08/29/2022] [Indexed: 12/14/2022] Open
Abstract
Oxaliplatin (OHP)-induced peripheral neurotoxicity (OIPN) is a frequent adverse event of colorectal cancer treatment. OIPN encompasses a chronic and an acute syndrome. The latter consists of transient axonal hyperexcitability, due to unbalance in Na+ voltage-operated channels (Na+VOC). This leads to sustained depolarisation which can activate the reverse mode of the Na+/Ca2+ exchanger 2 (NCX2), resulting in toxic Ca2+ accumulation and axonal damage (ADa). We explored the role of NCX2 in in vitro and in vivo settings. Embryonic rat Dorsal Root Ganglia (DRG) organotypic cultures treated with SEA0400 (SEA), a NCX inhibitor, were used to assess neuroprotection in a proof-of-concept and pilot study to exploit NCX modulation to prevent ADa. In vivo, OHP treated mice (7 mg/Kg, i.v., once a week for 8 weeks) were compared with a vehicle-treated group (n = 12 each). Neurophysiological and behavioural testing were performed to characterise acute and chronic OIPN, and morphological analyses were performed to detect ADa. Immunohistochemistry, immunofluorescence, and western blotting (WB) analyses were also performed to demonstrate changes in NCX2 immunoreactivity and protein expression. In vitro, NCX inhibition was matched by ADa mitigation. In the in vivo part, after verifyingboth acute and chronic OIPN had ensued, we confirmed via immunohistochemistry, immunofluorescence, and WB that a significant NCX2 alteration had ensued in the OHP group. Our data suggest NCX2 involvement in ADa development, paving the way to a new line of research to prevent OIPN.
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Affiliation(s)
- Elisa Ballarini
- School of Medicine and Surgery, University of Milano-Bicocca, 20126 Milan, Italy
- NeuroMI (Milan Center for Neuroscience), 20126 Milan, Italy
| | - Alessio Malacrida
- School of Medicine and Surgery, University of Milano-Bicocca, 20126 Milan, Italy
- NeuroMI (Milan Center for Neuroscience), 20126 Milan, Italy
| | - Virginia Rodriguez-Menendez
- School of Medicine and Surgery, University of Milano-Bicocca, 20126 Milan, Italy
- NeuroMI (Milan Center for Neuroscience), 20126 Milan, Italy
| | - Eleonora Pozzi
- School of Medicine and Surgery, University of Milano-Bicocca, 20126 Milan, Italy
- NeuroMI (Milan Center for Neuroscience), 20126 Milan, Italy
| | - Annalisa Canta
- School of Medicine and Surgery, University of Milano-Bicocca, 20126 Milan, Italy
- NeuroMI (Milan Center for Neuroscience), 20126 Milan, Italy
| | - Alessia Chiorazzi
- School of Medicine and Surgery, University of Milano-Bicocca, 20126 Milan, Italy
- NeuroMI (Milan Center for Neuroscience), 20126 Milan, Italy
| | - Laura Monza
- School of Medicine and Surgery, University of Milano-Bicocca, 20126 Milan, Italy
- NeuroMI (Milan Center for Neuroscience), 20126 Milan, Italy
| | - Sara Semperboni
- School of Medicine and Surgery, University of Milano-Bicocca, 20126 Milan, Italy
- NeuroMI (Milan Center for Neuroscience), 20126 Milan, Italy
| | - Cristina Meregalli
- School of Medicine and Surgery, University of Milano-Bicocca, 20126 Milan, Italy
- NeuroMI (Milan Center for Neuroscience), 20126 Milan, Italy
| | - Valentina Alda Carozzi
- School of Medicine and Surgery, University of Milano-Bicocca, 20126 Milan, Italy
- NeuroMI (Milan Center for Neuroscience), 20126 Milan, Italy
| | - Maryamsadat Hashemi
- School of Medicine and Surgery, University of Milano-Bicocca, 20126 Milan, Italy
- NeuroMI (Milan Center for Neuroscience), 20126 Milan, Italy
| | - Gabriella Nicolini
- School of Medicine and Surgery, University of Milano-Bicocca, 20126 Milan, Italy
- NeuroMI (Milan Center for Neuroscience), 20126 Milan, Italy
| | - Arianna Scuteri
- School of Medicine and Surgery, University of Milano-Bicocca, 20126 Milan, Italy
- NeuroMI (Milan Center for Neuroscience), 20126 Milan, Italy
| | - Stephen N. Housley
- Integrated Cancer Research Center, School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Guido Cavaletti
- School of Medicine and Surgery, University of Milano-Bicocca, 20126 Milan, Italy
- NeuroMI (Milan Center for Neuroscience), 20126 Milan, Italy
| | - Paola Alberti
- School of Medicine and Surgery, University of Milano-Bicocca, 20126 Milan, Italy
- NeuroMI (Milan Center for Neuroscience), 20126 Milan, Italy
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The Evidence for Effective Inhibition of INa Produced by Mirogabalin ((1R,5S,6S)-6-(aminomethyl)-3-ethyl-bicyclo [3.2.0] hept-3-ene-6-acetic acid), a Known Blocker of Ca V Channels. Int J Mol Sci 2022; 23:ijms23073845. [PMID: 35409204 PMCID: PMC8998350 DOI: 10.3390/ijms23073845] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 03/28/2022] [Accepted: 03/29/2022] [Indexed: 01/27/2023] Open
Abstract
Mirogabalin (MGB, Tarlige®), an inhibitor of the α2δ-1 subunit of voltage-gated Ca2+ (CaV) channels, is used as a way to alleviate peripheral neuropathic pain and diabetic neuropathy. However, to what extent MGB modifies the magnitude, gating, and/or hysteresis of various types of plasmalemmal ionic currents remains largely unexplored. In pituitary tumor (GH3) cells, we found that MGB was effective at suppressing the peak (transient, INa(T)) and sustained (late, INa(L)) components of the voltage-gated Na+ current (INa) in a concentration-dependent manner, with an effective IC50 of 19.5 and 7.3 μM, respectively, while the KD value calculated on the basis of minimum reaction scheme was 8.2 μM. The recovery of INa(T) inactivation slowed in the presence of MGB, although the overall current-voltage relation of INa(T) was unaltered; however, there was a leftward shift in the inactivation curve of the current. The magnitude of the window (INa(W)) or resurgent INa (INa(R)) evoked by the respective ascending or descending ramp pulse (Vramp) was reduced during cell exposure to MGB. MGB-induced attenuation in INa(W) or INa(R) was reversed by the further addition of tefluthrin, a pyrethroid insecticide known to stimulate INa. MGB also effectively lessened the strength of voltage-dependent hysteresis of persistent INa in response to the isosceles triangular Vramp. The cumulative inhibition of INa(T), evoked by pulse train stimulation, was enhanced in its presence. Taken together, in addition to the inhibition of CaV channels, the NaV channel attenuation produced by MGB might have an impact in its analgesic effects occurring in vivo.
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Horváth B, Szentandrássy N, Almássy J, Dienes C, Kovács ZM, Nánási PP, Banyasz T. Late Sodium Current of the Heart: Where Do We Stand and Where Are We Going? Pharmaceuticals (Basel) 2022; 15:ph15020231. [PMID: 35215342 PMCID: PMC8879921 DOI: 10.3390/ph15020231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 02/07/2022] [Accepted: 02/09/2022] [Indexed: 02/05/2023] Open
Abstract
Late sodium current has long been linked to dysrhythmia and contractile malfunction in the heart. Despite the increasing body of accumulating information on the subject, our understanding of its role in normal or pathologic states is not complete. Even though the role of late sodium current in shaping action potential under physiologic circumstances is debated, it’s unquestioned role in arrhythmogenesis keeps it in the focus of research. Transgenic mouse models and isoform-specific pharmacological tools have proved useful in understanding the mechanism of late sodium current in health and disease. This review will outline the mechanism and function of cardiac late sodium current with special focus on the recent advances of the area.
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Affiliation(s)
- Balázs Horváth
- Department of Physiology, University of Debrecen, 4032 Debrecen, Hungary; (B.H.); (N.S.); (J.A.); (C.D.); (Z.M.K.); (P.P.N.)
| | - Norbert Szentandrássy
- Department of Physiology, University of Debrecen, 4032 Debrecen, Hungary; (B.H.); (N.S.); (J.A.); (C.D.); (Z.M.K.); (P.P.N.)
- Department of Basic Medical Sciences, Faculty of Dentistry, University of Debrecen, 4032 Debrecen, Hungary
| | - János Almássy
- Department of Physiology, University of Debrecen, 4032 Debrecen, Hungary; (B.H.); (N.S.); (J.A.); (C.D.); (Z.M.K.); (P.P.N.)
| | - Csaba Dienes
- Department of Physiology, University of Debrecen, 4032 Debrecen, Hungary; (B.H.); (N.S.); (J.A.); (C.D.); (Z.M.K.); (P.P.N.)
| | - Zsigmond Máté Kovács
- Department of Physiology, University of Debrecen, 4032 Debrecen, Hungary; (B.H.); (N.S.); (J.A.); (C.D.); (Z.M.K.); (P.P.N.)
| | - Péter P. Nánási
- Department of Physiology, University of Debrecen, 4032 Debrecen, Hungary; (B.H.); (N.S.); (J.A.); (C.D.); (Z.M.K.); (P.P.N.)
- Department of Dental Physiology and Pharmacology, University of Debrecen, 4032 Debrecen, Hungary
| | - Tamas Banyasz
- Department of Physiology, University of Debrecen, 4032 Debrecen, Hungary; (B.H.); (N.S.); (J.A.); (C.D.); (Z.M.K.); (P.P.N.)
- Correspondence: ; Tel.: +36-(52)-255-575; Fax: +36-(52)-255-116
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Eugenol interacts with cardiac sodium channel and reduces heart excitability and arrhythmias. Life Sci 2021; 282:119761. [PMID: 34217764 DOI: 10.1016/j.lfs.2021.119761] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 06/14/2021] [Accepted: 06/24/2021] [Indexed: 11/22/2022]
Abstract
AIMS Eugenol is a natural compound found in the essential oils of many aromatic plants. The compound is used as a local anesthetic because of its inhibitory effect on the voltage-gated Na+ channels (Nav), which are expressed in the nociceptive neurons. Eugenol has shown wide range of activities in the cardiovascular system; most of these activities are attributed to the modulation of voltage-sensitive Ca2+ channels. However, its action on Nav1.5, the main subtype of Nav expressed in the mammalian myocardium, is unknown. The interaction of eugenol with Nav1.5 could also contribute to its antiarrhythmic properties in vitro and ex vivo. We investigated the compound's effect on sodium current (INa) and its possible cardiac antiarrhythmic activity. METHODS The effect of eugenol on cardiac contractility was investigated using isolated atrium from guinea pig (for isometric force measurements). The compound's effect on INa was evaluated using human embryonic cell transiently expressing human Nav1.5 and patch-clamp technique. KEY FINDINGS Eugenol caused negative inotropic and chronotropic effects in the atria. In the ex vivo arrhythmia model, eugenol decreased atrial pacing disturbance induced by ouabain. Eugenol reduced the INa in a concentration-dependent manner. Furthermore, the compound left-shifted the stationary inactivation curve, delayed recovery from inactivation of the INa, and preferentially blocked the channel in the inactivated state. Importantly, eugenol was able to attenuate the late sodium current. All these aspects are considered to be antiarrhythmic. SIGNIFICANCE Overall, our findings demonstrate that eugenol has antiarrhythmic activity due, at least in part, to its interaction with Nav1.5.
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Song L, Zhang ZF, Hu LK, Zhang PH, Cao ZZ, Liu ZP, Zhang PP, Ma JH. Curcumin, a Multi-Ion Channel Blocker That Preferentially Blocks Late Na + Current and Prevents I/R-Induced Arrhythmias. Front Physiol 2020; 11:978. [PMID: 32973546 PMCID: PMC7472421 DOI: 10.3389/fphys.2020.00978] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Accepted: 07/20/2020] [Indexed: 11/13/2022] Open
Abstract
Increasing evidence shows that Curcumin (Cur) has a protective effect against cardiovascular diseases. However, the role of Cur in the electrophysiology of cardiomyocytes is currently not entirely understood. Therefore, the present study was conducted to investigate the effects of Cur on the action potential and transmembrane ion currents in rabbit ventricular myocytes to explore its antiarrhythmic property. The whole-cell patch clamp was used to record the action potential and ion currents, while the multichannel acquisition and analysis system was used to synchronously record the electrocardiogram and monophasic action potential. The results showed that 30 μmol/L Cur shortened the 50 and 90% repolarization of action potential by 17 and 7%, respectively. In addition, Cur concentration dependently inhibited the Late-sodium current (I Na.L), Transient-sodium current (I Na.T), L-type calcium current (I Ca.L), and Rapidly delayed rectifying potassium current (I Kr), with IC50 values of 7.53, 398.88, 16.66, and 9.96 μmol/L, respectively. Importantly, the inhibitory effect of Cur on I Na.L was 52.97-fold higher than that of I Na.T. Moreover, Cur decreased ATX II-prolonged APD, suppressed the ATX II-induced early afterdepolarization (EAD) and Ca2+-induced delayed afterdepolarization (DAD) in ventricular myocytes, and reduced the occurrence and average duration of ventricular tachycardias and ventricular fibrillations induced by ischemia-reperfusion injury. In conclusion, Cur inhibited I Na.L, I Na.T, I Ca.L, and I Kr; shortened APD; significantly suppressed EAD and DAD-like arrhythmogenic activities at the cellular level; and exhibited antiarrhythmic effect at the organ level. It is first revealed that Cur is a multi-ion channel blocker that preferentially blocks I Na.L and may have potential antiarrhythmic property.
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Affiliation(s)
- Lv Song
- Cardio-Electrophysiological Research Laboratory, Medical College of Wuhan University of Science and Technology, Wuhan, China.,College of Life Science and Health, Wuhan University of Science and Technology, Wuhan, China.,Hubei Province Key Laboratory of Occupational Hazard Identification and Control, Medical College of Wuhan University of Science and Technology, Wuhan, China
| | - Ze-Fu Zhang
- Cardio-Electrophysiological Research Laboratory, Medical College of Wuhan University of Science and Technology, Wuhan, China.,Hubei Province Key Laboratory of Occupational Hazard Identification and Control, Medical College of Wuhan University of Science and Technology, Wuhan, China
| | - Liang-Kun Hu
- Tianyou Hospital Affiliated to Wuhan University of Science and Technology, Wuhan, China
| | - Pei-Hua Zhang
- Cardio-Electrophysiological Research Laboratory, Medical College of Wuhan University of Science and Technology, Wuhan, China.,Hubei Province Key Laboratory of Occupational Hazard Identification and Control, Medical College of Wuhan University of Science and Technology, Wuhan, China
| | - Zhen-Zhen Cao
- Cardio-Electrophysiological Research Laboratory, Medical College of Wuhan University of Science and Technology, Wuhan, China.,Hubei Province Key Laboratory of Occupational Hazard Identification and Control, Medical College of Wuhan University of Science and Technology, Wuhan, China
| | - Zhi-Pei Liu
- Cardio-Electrophysiological Research Laboratory, Medical College of Wuhan University of Science and Technology, Wuhan, China.,Hubei Province Key Laboratory of Occupational Hazard Identification and Control, Medical College of Wuhan University of Science and Technology, Wuhan, China
| | - Pei-Pei Zhang
- Cardio-Electrophysiological Research Laboratory, Medical College of Wuhan University of Science and Technology, Wuhan, China.,Hubei Province Key Laboratory of Occupational Hazard Identification and Control, Medical College of Wuhan University of Science and Technology, Wuhan, China
| | - Ji-Hua Ma
- Cardio-Electrophysiological Research Laboratory, Medical College of Wuhan University of Science and Technology, Wuhan, China.,College of Life Science and Health, Wuhan University of Science and Technology, Wuhan, China.,Hubei Province Key Laboratory of Occupational Hazard Identification and Control, Medical College of Wuhan University of Science and Technology, Wuhan, China
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Khazraei H, Mirkhani H, Shabbir W. Electrocardiological effects of ranolazine and lidocaine on normal and diabetic rat atrium. J Interv Card Electrophysiol 2020; 60:387-394. [PMID: 32328860 DOI: 10.1007/s10840-020-00742-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 03/30/2020] [Indexed: 12/19/2022]
Abstract
PURPOSE Cellular changes occurring in diabetic cardiomyopathy include disturbances of calcium and sodium homeostasis. Voltage-gated sodium channels are responsible for the initiation of cardiac action potentials, and the excitability would create relevance. The effect of ranolazine as a sodium channel blocker on atrium electromechanical parameters is investigated and compared with lidocaine in streptozocin-treated diabetic rats. METHODS After an 8-week induction of diabetes type I, the effect of cumulative concentrations of ranolazine and lidocaine on the electrophysiology of isolated atrium was studied. Ranolazine's effects were evaluated on cardiac sodium current in normal- and high-glucose medium, with whole-cell patch-clamp technique. RESULTS Ranolazine at therapeutic concentrations had no significant statistical effect on refractory period in normal and diabetic isolated heart. Ranolazine (10 μM) caused a hyperpolarizing shift of V1/2 for steady-state inactivation in normal media, while it significantly elicited a depolarizing shift in high-glucose media (p < 0.05). CONCLUSION It is concluded that in the isolated rat atrium preparation, ranolazine and lidocaine have no beneficial on diabetic cardiomyopathy. Although refractoriness and contractility were not much different in normal and diabetic atria, there was a definite effect of ranolazine and lidocaine on sodium current in varying concentrations. This may have significance in future therapeutics.
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Affiliation(s)
- Hajar Khazraei
- Colorectal research center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Hossein Mirkhani
- Department of pharmacology, Shiraz University of Medical Sciences, Shiraz, Iran.
| | - Waheed Shabbir
- Department of Pharmacology and Toxicology, University of Vienna, A-1090, Vienna, Austria
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Ezeani M, Elom S. Necessity to evaluate PI3K/Akt signalling pathway in proarrhythmia. Open Heart 2017; 4:e000596. [PMID: 29259786 PMCID: PMC5729307 DOI: 10.1136/openhrt-2017-000596] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Revised: 11/13/2017] [Accepted: 11/19/2017] [Indexed: 01/04/2023] Open
Abstract
The incidence of QT prolongation and torsades de pointes is on the rise due to the use of cardiovascular and non-cardiovascular drugs. Robust efforts have been made and are still ongoing to understand the underlying mechanisms that can enhance or prevent the development of drug-induced proarrhythmia. A caveat in the use of antiarrhythmic drugs is the ability to obtain safe action potential prolongation therapeutic effects, through IKr blockade. This remains as yet completely unachievable, as blockers of the potassium channel have not provided complete safe measures. Because of this, efforts at understanding the mechanisms of proarrhythmia have continued. PI3K/Akt signalling pathway appears to possess some potential advantage in this regard because cardiomyocytes intracellular dialysis with phosphatidylinositol (3,4,5)-trisphosphate (PIP3) normalises ion channel alterations and eliminates proarrhythmic features. However, there is a conundrum. Increased activities of PIP3 signalling can enhance cell proliferation and survival, and reduced activities of PIP3 signalling can lead to proarrhythmia. PI3K inhibitors used in cancer treatment have been found to cause proarrhythmia, and represent a potential avenue for the research and evaluation of potential effectiveness of a battery of antiarrhythmic and cancer drugs that are either currently in use or in development. Despite this knowledge, limited information is available on PI3K/Akt signalling and arrhythmogenesis. This highlights the need to search for new ways to improve testing of antiarrhythmic drugs and increase our understanding in PI3K/Akt signalling and arrhythmogenesis.
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Affiliation(s)
- Martin Ezeani
- Department of Chemical Pathology, Faculty of Health Science and Technology, College of Health Science, Ebonyi State University, Abakaliki, Ebonyi State, Nigeria
| | - Sunday Elom
- Department of Medical Biochemistry, Federal University Ndufu-Alike, Ikwo, Ebonyi State, Nigeria
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Azam MA, Zamiri N, Massé S, Kusha M, Lai PFH, Nair GK, Tan NS, Labos C, Nanthakumar K. Effects of Late Sodium Current Blockade on Ventricular Refibrillation in a Rabbit Model. Circ Arrhythm Electrophysiol 2017; 10:CIRCEP.116.004331. [PMID: 28314848 DOI: 10.1161/circep.116.004331] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 01/19/2017] [Indexed: 12/19/2022]
Abstract
BACKGROUND After defibrillation of initial ventricular fibrillation (VF), it is crucial to prevent refibrillation to ensure successful resuscitation outcomes. Inability of the late Na+ current to inactivate leads to intracellular Ca2+ dysregulation and arrhythmias. Our aim was to determine the effects of ranolazine and GS-967, inhibitors of the late Na+ current, on ventricular refibrillation. METHODS AND RESULTS Long-duration VF was induced electrically in Langendorff-perfused rabbit hearts (n=22) and terminated with a defibrillator after 6 minutes. Fibrillating hearts were randomized into 3 groups: treatment with ranolazine, GS-967, or nontreated controls. In the treated groups, hearts were perfused with ranolazine or GS-967 at 2 minutes of VF. In control experiments, perfusion solution was supplemented with isotonic saline in lieu of a drug. Inducibility of refibrillation was assessed after initial long-duration VF by attempting to reinduce VF. Sustained refibrillation was successful in fewer ranolazine-treated (29.17%; P=0.005) or GS-967-treated (45.83%, P=0.035) hearts compared with that in nontreated control hearts (84.85%). In GS-967-treated hearts, significantly more spontaneous termination of initial long-duration VF was observed (66.67%; P=0.01). Ca2+ transient duration was reduced in ranolazine-treated hearts compared with that in controls (P=0.05) and also Ca2+ alternans (P=0.03). CONCLUSIONS Late Na+ current inhibition during long-duration VF reduces the susceptibility to subsequent refibrillation, partially by mitigating dysregulation of intracellular Ca2+. These results suggest the potential therapeutic use of ranolazine and GS-967 and call for further testing in cardiac arrest models.
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Affiliation(s)
- Mohammed Ali Azam
- From the Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, University Health Network, Ontario, Canada (M.A.A., N.Z., S.M., M.K., P.F.H.L., G.K.N., N.S.T., K.N.); and Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada (C.L.)
| | - Nima Zamiri
- From the Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, University Health Network, Ontario, Canada (M.A.A., N.Z., S.M., M.K., P.F.H.L., G.K.N., N.S.T., K.N.); and Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada (C.L.)
| | - Stéphane Massé
- From the Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, University Health Network, Ontario, Canada (M.A.A., N.Z., S.M., M.K., P.F.H.L., G.K.N., N.S.T., K.N.); and Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada (C.L.)
| | - Marjan Kusha
- From the Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, University Health Network, Ontario, Canada (M.A.A., N.Z., S.M., M.K., P.F.H.L., G.K.N., N.S.T., K.N.); and Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada (C.L.)
| | - Patrick F H Lai
- From the Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, University Health Network, Ontario, Canada (M.A.A., N.Z., S.M., M.K., P.F.H.L., G.K.N., N.S.T., K.N.); and Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada (C.L.)
| | - Govind K Nair
- From the Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, University Health Network, Ontario, Canada (M.A.A., N.Z., S.M., M.K., P.F.H.L., G.K.N., N.S.T., K.N.); and Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada (C.L.)
| | - Nigel S Tan
- From the Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, University Health Network, Ontario, Canada (M.A.A., N.Z., S.M., M.K., P.F.H.L., G.K.N., N.S.T., K.N.); and Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada (C.L.)
| | - Christopher Labos
- From the Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, University Health Network, Ontario, Canada (M.A.A., N.Z., S.M., M.K., P.F.H.L., G.K.N., N.S.T., K.N.); and Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada (C.L.)
| | - Kumaraswamy Nanthakumar
- From the Hull Family Cardiac Fibrillation Management Laboratory, Toronto General Hospital, University Health Network, Ontario, Canada (M.A.A., N.Z., S.M., M.K., P.F.H.L., G.K.N., N.S.T., K.N.); and Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada (C.L.).
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Ronchi C, Torre E, Rizzetto R, Bernardi J, Rocchetti M, Zaza A. Late sodium current and intracellular ionic homeostasis in acute ischemia. Basic Res Cardiol 2017; 112:12. [PMID: 28101642 DOI: 10.1007/s00395-017-0602-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 01/03/2017] [Indexed: 11/25/2022]
Abstract
Blockade of the late Na+ current (I NaL) protects from ischemia/reperfusion damage; nevertheless, information on changes in I NaL during acute ischemia and their effect on intracellular milieu is missing. I NaL, cytosolic Na+ and Ca2+ activities (Nacyt, Cacyt) were measured in isolated rat ventricular myocytes during 7 min of simulated ischemia (ISC); in all the conditions tested, effects consistently exerted by ranolazine (RAN) and tetrodotoxin (TTX) were interpreted as due to I NaL blockade. The results indicate that I NaL was enhanced during ISC in spite of changes in action potential (AP) contour; I NaL significantly contributed to Nacyt rise, but only marginally to Cacyt rise. The impact of I NaL on Cacyt was markedly enhanced by blockade of the sarcolemmal(s) Na+/Ca2+ exchanger (NCX) and was due to the presence of (Na+-sensitive) Ca2+ efflux through mitochondrial NCX (mNCX). sNCX blockade increased Cacyt and decreased Nacyt, thus indicating that, throughout ISC, sNCX operated in the forward mode, in spite of the substantial Nacyt increment. Thus, a robust Ca2+ source, other than sNCX and including mitochondria, contributed to Cacyt during ISC. Most, but not all, of RAN effects were shared by TTX. (1) The paradigm that attributes Cacyt accumulation during acute ischemia to decrease/reversal of sNCX transport may not be of general applicability; (2) I NaL is enhanced during ISC, when the effect of Nacyt on mitochondrial Ca2+ transport may substantially contribute to I NaL impact on Cacyt; (3) RAN may act mostly, but not exclusively, through I NaL blockade during ISC.
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Affiliation(s)
- Carlotta Ronchi
- Department of Biotechnologies and Biosciences, University Milano-Bicocca, Piazza della Scienza 2, 20126, Milan, Italy
| | - Eleonora Torre
- Department of Biotechnologies and Biosciences, University Milano-Bicocca, Piazza della Scienza 2, 20126, Milan, Italy
| | - Riccardo Rizzetto
- Department of Biotechnologies and Biosciences, University Milano-Bicocca, Piazza della Scienza 2, 20126, Milan, Italy
| | - Joyce Bernardi
- Department of Biotechnologies and Biosciences, University Milano-Bicocca, Piazza della Scienza 2, 20126, Milan, Italy
| | - Marcella Rocchetti
- Department of Biotechnologies and Biosciences, University Milano-Bicocca, Piazza della Scienza 2, 20126, Milan, Italy
| | - Antonio Zaza
- Department of Biotechnologies and Biosciences, University Milano-Bicocca, Piazza della Scienza 2, 20126, Milan, Italy.
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Pre- and Delayed Treatments With Ranolazine Ameliorate Ventricular Arrhythmias and Nav1.5 Downregulation in Ischemic/Reperfused Rat Hearts. J Cardiovasc Pharmacol 2016; 68:269-279. [DOI: 10.1097/fjc.0000000000000412] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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12
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Müller-Edenborn B, Kania G, Osto E, Jakob P, Krasniqi N, Beck-Schimmer B, Blyszczuk P, Eriksson U. Lidocaine Enhances Contractile Function of Ischemic Myocardial Regions in Mouse Model of Sustained Myocardial Ischemia. PLoS One 2016; 11:e0154699. [PMID: 27140425 PMCID: PMC4854463 DOI: 10.1371/journal.pone.0154699] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Accepted: 04/18/2016] [Indexed: 12/28/2022] Open
Abstract
RATIONALE Perioperative myocardial ischemia is common in high-risk patients. The use of interventional revascularisation or even thrombolysis is limited in this patient subset due to exceedingly high bleeding risks. Blockade of voltage-gated sodium channels (VGSC) with lidocaine had been suggested to reduce infarct size and cardiomyocyte cell death in ischemia/reperfusion models. However, the impact of lidocaine on cardiac function during sustained ischemia still remains unclear. METHODS Sustained myocardial ischemia was induced by ligation of the left anterior descending artery in 12-16 weeks old male BALB/c mice. Subcutaneous lidocaine (30 mg/kg) was used to block VGSC. Cardiac function was quantified at baseline and at 72h by conventional and speckle-tracking based echocardiography to allow high-sensitivity in vivo phenotyping. Infarct size and cardiomyocyte cell death were assessed post mortem histologically and indirectly using troponin measurements. RESULTS Ischemia strongly impaired both, global systolic and diastolic function, which were partially rescued in lidocaine treated in mice. No differences regarding infarct size and cardiomyocyte cell death were observed. Mechanistically, and as shown with speckle-tracking analysis, lidocaine specifically improves residual contractility in the ischemic but not in the remote, non-ischemic myocardium. CONCLUSION VGSC blockade with lidocaine rescues function of ischemic myocardium as a potential bridging to revascularisation in the setting of perioperative myocardial ischemia.
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Affiliation(s)
- Björn Müller-Edenborn
- Cardioimmunology, Center of Molecular Cardiology, University of Zurich, Wagistr. 12, CH-8952, Schlieren, Switzerland.,Institute of Physiology, University of Zurich, Winterthurerstr. 190, CH-8057 Zurich, Switzerland
| | - Gabriela Kania
- Research of Systemic Autoimmune Diseases, Division of Rheumatology, University Hospital Zurich, Wagistr. 14, CH-8952 Schlieren, Switzerland
| | - Elena Osto
- Center of Molecular Cardiology, University of Zurich, Wagistr. 12, CH-8952 Schlieren, Switzerland.,Laboratory of Translational Nutrition Biology, Eidgenössische Technische Hochschule Zürich, Schorenstrasse 16, 8603 Schwerzenbach, Switzerland
| | - Philipp Jakob
- Center of Molecular Cardiology, University of Zurich, Wagistr. 12, CH-8952 Schlieren, Switzerland.,Department of Cardiology, University Heart Center, University Hospital Zurich, Raemistr. 100, CH-8001, Zurich, Switzerland
| | - Nazmi Krasniqi
- Department of Medicine, GZO-Zurich Regional Health Center, Spitalstr. 66, CH-8620, Wetzikon, Switzerland.,Department of Cardiology, University Heart Center, University Hospital Zurich, Raemistr. 100, CH-8001, Zurich, Switzerland
| | - Beatrice Beck-Schimmer
- Institute of Physiology, University of Zurich, Winterthurerstr. 190, CH-8057 Zurich, Switzerland.,Institute of Anesthesiology, University Heart Center, University Hospital Zurich, Raemistr. 100, CH-8001, Zurich, Switzerland
| | - Przemyslaw Blyszczuk
- Cardioimmunology, Center of Molecular Cardiology, University of Zurich, Wagistr. 12, CH-8952, Schlieren, Switzerland
| | - Urs Eriksson
- Cardioimmunology, Center of Molecular Cardiology, University of Zurich, Wagistr. 12, CH-8952, Schlieren, Switzerland.,Department of Medicine, GZO-Zurich Regional Health Center, Spitalstr. 66, CH-8620, Wetzikon, Switzerland.,Department of Cardiology, University Heart Center, University Hospital Zurich, Raemistr. 100, CH-8001, Zurich, Switzerland
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13
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Calderón-Sánchez EM, Domínguez-Rodríguez A, López-Haldón J, Jiménez-Navarro MF, Gómez AM, Smani T, Ordóñez A. Cardioprotective Effect of Ranolazine in the Process of Ischemia-reperfusion in Adult Rat Cardiomyocytes. ACTA ACUST UNITED AC 2016; 69:45-53. [DOI: 10.1016/j.rec.2015.02.027] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 02/27/2015] [Indexed: 12/19/2022]
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14
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Efecto cardioprotector de la ranolazina en el proceso de isquemia-reperfusión en cardiomiocitos de rata adultos. Rev Esp Cardiol 2016. [DOI: 10.1016/j.recesp.2015.02.027] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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15
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Wu Y, Wang L, Ma J, Song Y, Zhang P, Luo A, Fu C, Cao Z, Wang X, Shryock JC, Belardinelli L. Protein kinase C and Ca(2+) -calmodulin-dependent protein kinase II mediate the enlarged reverse INCX induced by ouabain-increased late sodium current in rabbit ventricular myocytes. Exp Physiol 2015; 100:399-409. [PMID: 25641541 DOI: 10.1113/expphysiol.2014.083972] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Accepted: 01/23/2015] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? What are the effects of protein kinase C (PKC) and Ca(2+) -calmodulin-dependent protein kinase II (CaMKII) on late sodium current (INaL ), reverse Na(+) -Ca(2+) exchange current (reverse INCX ) or intracellular Ca(2+) levels changed by ouabain? What is the main finding and its importance? Ouabain, even at low concentrations (0.5-8.0 μm), can increase INaL and reverse INCX , and these effects may contribute to the effect of the glycoside to increase Ca(2+) transients and contractility. Both PKC and CaMKII activities may mediate or modulate these processes. It has been reported that the cardiac glycoside ouabain can increase the late sodium current (INaL ), as well as the diastolic intracellular calcium concentration and contractile shortening. Whether an increase of INaL participates in a pathway that can mediate the positive inotropic response to ouabain is unknown. We therefore determined the effects of ouabain on INaL , reverse Na(+) -Ca(2+) exchange current (reverse INCX ), intracellular Ca(2+) ([Ca(2+) ]i ) levels and contractile shortening in rabbit isolated ventricular myocytes. Ouabain (0.1-8 μm) markedly increased INaL and reverse INCX in a concentration-dependent manner, with significant effects at concentrations as low as 0.5 and 1 μm. These effects of ouabain were suppressed by the INaL inhibitors TTX and ranolazine, the protein kinase C inhibitor bisindolylmaleimide and the Ca(2+) -calmodulin-dependent protein kinase II inhibitor KN-93. The enhancement by 0.5 μm ouabain of ventricular myocyte contractility and intracellular Ca(2+) transients was suppressed by 2.0 μm TTX. We conclude that ouabain, even at low concentrations (0.5-8.0 μm), can increase INaL and reverse INCX , and these effects may contribute to the effect of the glycoside to increase Ca(2+) transients and contractility. Both protein kinase C and Ca(2+) -calmodulin-dependent protein kinase II activities may mediate or modulate these processes.
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Affiliation(s)
- Ying Wu
- Cardio-Electrophysiological Research Laboratory, Medical College of Wuhan University of Science and Technology, Wuhan, China
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16
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Chang CJ, Cheng CC, Yang TF, Chen YC, Lin YK, Chen SA, Chen YJ. Selective and non-selective non-steroidal anti-inflammatory drugs differentially regulate pulmonary vein and atrial arrhythmogenesis. Int J Cardiol 2015; 184:559-567. [PMID: 25767017 DOI: 10.1016/j.ijcard.2015.03.066] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Revised: 01/12/2015] [Accepted: 03/03/2015] [Indexed: 12/30/2022]
Abstract
BACKGROUND Non-steroidal anti-inflammatory drugs (NSAIDs) increase the risk of atrial fibrillation (AF). This study investigated whether selective and non-selective NSAIDs differentially regulate the arrhythmogenesis of pulmonary veins and atria. METHODS Conventional microelectrodes were used to record action potentials (APs) in isolated rabbit PVs, sinoatrial node (SAN), left atrium (LA), and right atrium (RA) preparations before and after celecoxib or indomethacin administration. A whole-cell patch clamp was used to record the sodium-calcium exchanger (NCX) current, L-type calcium current (ICa-L), and late sodium current (INa-late) before and after celecoxib administration in isolated PV cardiomyocytes. RESULTS Celecoxib (0.3, 1, and 3 μM) reduced PV spontaneous beating rates, and induced delayed afterdepolarizations and burst firings in four of eight PV preparations (50%, p<0.05). Celecoxib also reduced SAN beating rates and decreased AP durations (APDs) in RA and LA, but did not change the resting membrane potential. Indomethacin (0.3, 1, 3, and 10 μM) changed neither the PV or SAN beating rates nor RA APDs, but it reduced LA APDs. Celecoxib (3 μM) significantly increased the NCX current and decreased the ICa-L, but did not change the INa-late. Ranolazine (10 μM) suppressed celecoxib (3 μM)-induced PV burst firings in 6 (86%, p<0.05) of 7 PVs. KB-R7943 (10 μM) suppressed celecoxib (3 μM)-induced PV burst firings in 5 (71%, p<0.05) of 7 PVs. CONCLUSIONS Selective and non-selective NSAIDs differentially modulate PV and atrial electrophysiological characteristics. Celecoxib increased PV triggered activity through enhancement of the NCX current, which contributed to its arrhythmogenesis.
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Affiliation(s)
- Chien-Jung Chang
- Department of Biological Science and Technology, National Chiao Tung University, Hsinchu, Taiwan; Division of Cardiology, Tungs' Taichung MetroHarbor Hospital, Taichung, Taiwan
| | - Chen-Chuan Cheng
- Division of Cardiology, Chi-Mei Medical Center, Tainan, Taiwan; School of Medicine, Chung Shan Medical University, Taichung, Taiwan
| | - Ten-Fang Yang
- Department of Biological Science and Technology, National Chiao Tung University, Hsinchu, Taiwan
| | - Yao-Chang Chen
- Department of Biomedical Engineering, and Institute of Physiology, National Defense Medical Center, Taipei, Taiwan
| | - Yung-Kuo Lin
- Division of Cardiovascular Medicine, Department of Internal Medicine, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan
| | - Shih-Ann Chen
- National Yang-Ming University, School of Medicine, Taipei, Taiwan; Division of Cardiology and Cardiovascular Research Center, Veterans General Hospital-Taipei, Taipei, Taiwan
| | - Yi-Jen Chen
- Division of Cardiovascular Medicine, Department of Internal Medicine, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan; Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
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17
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Kessler EL, Boulaksil M, van Rijen HVM, Vos MA, van Veen TAB. Passive ventricular remodeling in cardiac disease: focus on heterogeneity. Front Physiol 2014; 5:482. [PMID: 25566084 PMCID: PMC4273631 DOI: 10.3389/fphys.2014.00482] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Accepted: 11/24/2014] [Indexed: 12/20/2022] Open
Abstract
Passive ventricular remodeling is defined by the process of molecular ventricular adaptation to different forms of cardiac pathophysiology. It includes changes in tissue architecture, such as hypertrophy, fiber disarray, alterations in cell size and fibrosis. Besides that, it also includes molecular remodeling of gap junctions, especially those composed by Connexin43 proteins (Cx43) in the ventricles that affect cell-to-cell propagation of the electrical impulse, and changes in the sodium channels that modify excitability. All those alterations appear mainly in a heterogeneous manner, creating irregular and inhomogeneous electrical and mechanical coupling throughout the heart. This can predispose to reentry arrhythmias and adds to a further deterioration into heart failure. In this review, passive ventricular remodeling is described in Hypertrophic Cardiomyopathy (HCM), Dilated Cardiomyopathy (DCM), Ischemic Cardiomyopathy (ICM), and Arrhythmogenic Cardiomyopathy (ACM), with a main focus on the heterogeneity of those alterations mentioned above.
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Affiliation(s)
- Elise L Kessler
- Division of Heart and Lungs, Department of Medical Physiology, University Medical Center Utrecht Utrecht, Netherlands
| | - Mohamed Boulaksil
- Division of Heart and Lungs, Department of Medical Physiology, University Medical Center Utrecht Utrecht, Netherlands ; Department of Cardiology, Radboud University Medical Center Nijmegen, Netherlands
| | - Harold V M van Rijen
- Division of Heart and Lungs, Department of Medical Physiology, University Medical Center Utrecht Utrecht, Netherlands
| | - Marc A Vos
- Division of Heart and Lungs, Department of Medical Physiology, University Medical Center Utrecht Utrecht, Netherlands
| | - Toon A B van Veen
- Division of Heart and Lungs, Department of Medical Physiology, University Medical Center Utrecht Utrecht, Netherlands
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18
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Ranolazine ameliorates postresuscitation electrical instability and myocardial dysfunction and improves survival with good neurologic recovery in a rat model of cardiac arrest. Heart Rhythm 2014; 11:1641-7. [DOI: 10.1016/j.hrthm.2014.05.023] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Indexed: 12/19/2022]
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19
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Na+ dysregulation coupled with Ca2+ entry through NCX1 promotes muscular dystrophy in mice. Mol Cell Biol 2014; 34:1991-2002. [PMID: 24662047 DOI: 10.1128/mcb.00339-14] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Unregulated Ca(2+) entry is thought to underlie muscular dystrophy. Here, we generated skeletal-muscle-specific transgenic (TG) mice expressing the Na(+)-Ca(2+) exchanger 1 (NCX1) to model its identified augmentation during muscular dystrophy. The NCX1 transgene induced dystrophy-like disease in all hind-limb musculature, as well as exacerbated the muscle disease phenotypes in δ-sarcoglycan (Sgcd(-/-)), Dysf(-/-), and mdx mouse models of muscular dystrophy. Antithetically, muscle-specific deletion of the Slc8a1 (NCX1) gene diminished hind-limb pathology in Sgcd(-/-) mice. Measured increases in baseline Na(+) and Ca(2+) in dystrophic muscle fibers of the hind-limb musculature predicts a net Ca(2+) influx state due to reverse-mode operation of NCX1, which mediates disease. However, the opposite effect is observed in the diaphragm, where NCX1 overexpression mildly protects from dystrophic disease through a predicted enhancement in forward-mode NCX1 operation that reduces Ca(2+) levels. Indeed, Atp1a2(+/-) (encoding Na(+)-K(+) ATPase α2) mice, which have reduced Na(+) clearance rates that would favor NCX1 reverse-mode operation, showed exacerbated disease in the hind limbs of NCX1 TG mice, similar to treatment with the Na(+)-K(+) ATPase inhibitor digoxin. Treatment of Sgcd(-/-) mice with ranolazine, a broadly acting Na(+) channel inhibitor that should increase NCX1 forward-mode operation, reduced muscular pathology.
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Wang XJ, Wang LL, Fu C, Zhang PH, Wu Y, Ma JH. Ranolazine Attenuates the Enhanced Reverse Na+-Ca2+ Exchange Current via Inhibiting Hypoxia-Increased Late Sodium Current in Ventricular Myocytes. J Pharmacol Sci 2014; 124:365-73. [DOI: 10.1254/jphs.13202fp] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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21
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Moreau A, Krahn AD, Gosselin-Badaroudine P, Klein GJ, Christé G, Vincent Y, Boutjdir M, Chahine M. Sodium overload due to a persistent current that attenuates the arrhythmogenic potential of a novel LQT3 mutation. Front Pharmacol 2013; 4:126. [PMID: 24098284 PMCID: PMC3787509 DOI: 10.3389/fphar.2013.00126] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Accepted: 09/11/2013] [Indexed: 12/21/2022] Open
Abstract
Long QT syndrome (LQTS) is a congenital abnormality of cardiac repolarization that manifests as a prolonged QT interval on 12-lead electrocardiograms (ECGs). The syndrome may lead to syncope and sudden death from ventricular tachyarrhythmias known as torsades de pointes. An increased persistent Na+ current is known to cause a Ca2+ overload in case of ischemia for example. Such increased Na+ persistent current is also usually associated to the LQT3 syndrome. The purpose of this study was to investigate the pathological consequences of a novel mutation in a family affected by LQTS. The impact of biophysical defects on cellular homeostasis are also investigated. Genomic DNA was extracted from blood samples, and a combination of PCR and DNA sequencing of several LQTS-linked genes was used to identify mutations. The mutation was reproduced in vitro and was characterized using the patch clamp technique and in silico quantitative analysis. A novel mutation (Q1476R) was identified on the SCN5A gene encoding the cardiac Na+ channel. Cells expressing the Q1476R mutation exhibited biophysical alterations, including a shift of SS inactivation and a significant increase in the persistent Na+ current. The in silico analysis confirmed the arrhythmogenic character of the Q1476R mutation. It further revealed that the increase in persistent Na+ current causes a frequency-dependent Na+ overload in cardiomyocytes co-expressing WT and mutant Nav1.5 channels that, in turn, exerts a moderating effect on the lengthening of the action potential (AP) duration caused by the mutation. The Q1476R mutation in SCN5A results in a three-fold increase in the window current and a persistent inward Na+ current. These biophysical defects may expose the carrier of the mutation to arrhythmias that occur preferentially in the patient at rest or during tachycardia. However, the Na+ overload counterbalances the gain-of-function of the mutation and is beneficial in that it prevents severe arrhythmias at intermediate heart rates.
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Affiliation(s)
- Adrien Moreau
- Centre de Recherche de l'Institut Universitaire en Santé Mentale de Québec, Quebec City QC, Canada
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22
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Verrier RL, Kumar K, Nieminen T, Belardinelli L. Mechanisms of ranolazine's dual protection against atrial and ventricular fibrillation. Europace 2013; 15:317-24. [PMID: 23220484 PMCID: PMC3578672 DOI: 10.1093/europace/eus380] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Accepted: 10/22/2012] [Indexed: 12/19/2022] Open
Abstract
Coronary artery disease and heart failure carry concurrent risk for atrial fibrillation and life-threatening ventricular arrhythmias. We review evidence indicating that at therapeutic concentrations, ranolazine has potential for dual suppression of these arrhythmias. Mechanisms and clinical implications are discussed.
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Affiliation(s)
- Richard L Verrier
- Division of Cardiovascular Medicine, Harvard-Thorndike Electrophysiology Institute, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215-3908, USA.
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