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Autoantibodies in Atrial Fibrillation-State of the Art. Int J Mol Sci 2023; 24:ijms24031852. [PMID: 36768174 PMCID: PMC9916061 DOI: 10.3390/ijms24031852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 01/15/2023] [Accepted: 01/17/2023] [Indexed: 01/19/2023] Open
Abstract
Atrial fibrillation (AF) is the most common type of cardiac arrhythmia. To date, a lot of research has been conducted to investigate the underlying mechanisms of this disease at both molecular and cellular levels. There is increasing evidence suggesting that autoimmunity is an important factor in the initiation and perpetuation of AF. Autoantibodies are thought to play a pivotal role in the regulation of heart rhythm and the conduction system and, therefore, are associated with AF development. In this review, we have summarized current knowledge concerning the role of autoantibodies in AF development as well as their prognostic and predictive value in this disease. The establishment of the autoantibody profile of separate AF patient groups may appear to be crucial in terms of developing novel treatment approaches for those patients; however, the exact role of various autoantibodies in AF is still a matter of ongoing debate.
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Bazmi M, Escobar AL. Autonomic Regulation of the Goldfish Intact Heart. Front Physiol 2022; 13:793305. [PMID: 35222073 PMCID: PMC8864152 DOI: 10.3389/fphys.2022.793305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 01/19/2022] [Indexed: 11/13/2022] Open
Abstract
Autonomic regulation plays a central role in cardiac contractility and excitability in numerous vertebrate species. However, the role of autonomic regulation is less understood in fish physiology. Here, we used Goldfish as a model to explore the role of autonomic regulation. A transmural electrocardiogram recording showed perfusion of the Goldfish heart with isoproterenol increased the spontaneous heart rate, while perfusion with carbamylcholine decreased the spontaneous heart rate. Cardiac action potentials obtained via sharp microelectrodes exhibited the same modifications of the spontaneous heart rate in response to isoproterenol and carbamylcholine. Interestingly, the duration of the cardiac action potentials lengthened in the presence of both isoproterenol and carbamylcholine. To evaluate cardiac contractility, the Goldfish heart was perfused with the Ca2+ indicator Rhod-2 and ventricular epicardial Ca2+ transients were measured using Pulsed Local Field Fluorescence Microscopy. Following isoproterenol perfusion, the amplitude of the Ca2+ transient significantly increased, the half duration of the Ca2+ transient shortened, and there was an observable increase in the velocity of the rise time and fall time of the Ca2+ transient, all of which are compatible with the shortening of the action potential induced by isoproterenol perfusion. On the other hand, carbamylcholine perfusion significantly reduced the amplitude of the Ca2+ transient and increased the half duration of the Ca2+ transient. These results are interesting because the effect of carbamylcholine is opposite to what happens in classically used models, such as mouse hearts, and the autonomic regulation of the Goldfish heart is strikingly similar to what has been observed in larger mammalian models resembling humans.
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Affiliation(s)
- Maedeh Bazmi
- Quantitative Systems Biology Program, School of Natural Sciences, University of California, Merced, Merced, CA, United States
| | - Ariel L Escobar
- Department of Bioengineering, School of Engineering, University of California, Merced, Merced, CA, United States
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Baraibar AM, de Pascual R, Rodriguez Angulo HO, Mijares A, Hernández-Guijo JM. Pro-arrhythmogenic effects of Trypanosoma cruzi conditioned medium proteins in a model of bovine chromaffin cells. Parasitology 2021; 148:1612-1623. [PMID: 34384512 PMCID: PMC11010060 DOI: 10.1017/s003118202100130x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 07/07/2021] [Accepted: 07/08/2021] [Indexed: 11/05/2022]
Abstract
Asymptomatic sudden death is the principal cause of mortality in Chagas disease. There is little information about molecular mechanisms involved in the pathophysiology of malignant arrhythmias in Chagasic patients. Previous studies have involved Trypanosoma cruzi secretion proteins in the genesis of arrhythmias ex vivo, but the molecular mechanisms involved are still unresolved. Thus, the aim was to determine the effect of these secreted proteins on the cellular excitability throughout to test its effects on catecholamine secretion, sodium-, calcium-, and potassium-conductance and action potential (AP) firing. Conditioned medium was obtained from the co-culture of T. cruzi and Vero cells (African green monkey kidney cells) and ultra-filtered for concentrating immunogenic high molecular weight parasite proteins. Chromaffin cells were assessed with the parasite and Vero cells control medium. Parasite-secreted proteins induce catecholamine secretion in a dose-dependent manner. Additionally, T. cruzi conditioned medium induced depression of both calcium conductance and calcium and voltage-dependent potassium current. Interestingly, this fact was related to the abolishment of the hyperpolarization phase of the AP produced by the parasite medium. Taken together, these results suggest that T. cruzi proteins may be involved in the genesis of pro-arrhythmic conditions that could influence the appearance of malignant arrhythmias in Chagasic patients.
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Affiliation(s)
- A. M. Baraibar
- Department of Neuroscience, University of Minnesota, 4-158 Jackson Hall, 321 Church St s.e., Minneapolis, MN55455, USA
| | - R. de Pascual
- Department of Pharmacology and Therapeutic, Universidad Autónoma de Madrid, Av. Arzobispo Morcillo 4, 28029Madrid, Spain
- Institute ‘Teófilo Hernando’, Universidad Autónoma de Madrid, Av. Arzobispo Morcillo 4, 28029Madrid, Spain
| | - H. O. Rodriguez Angulo
- Laboratorio de Fisiología de Parásitos, Instituto Venezolano de Investigaciones Científicas, Caracas, Venezuela
| | - A. Mijares
- Laboratorio de Fisiología de Parásitos, Instituto Venezolano de Investigaciones Científicas, Caracas, Venezuela
| | - J. M. Hernández-Guijo
- Department of Pharmacology and Therapeutic, Universidad Autónoma de Madrid, Av. Arzobispo Morcillo 4, 28029Madrid, Spain
- Institute ‘Teófilo Hernando’, Universidad Autónoma de Madrid, Av. Arzobispo Morcillo 4, 28029Madrid, Spain
- IRYCIS, School of Medicine, Universidad Autónoma de Madrid, Av. Arzobispo Morcillo 4, 28029Madrid, Spain
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Bazmi M, Escobar AL. Excitation-Contraction Coupling in the Goldfish ( Carassius auratus) Intact Heart. Front Physiol 2020; 11:1103. [PMID: 33041845 PMCID: PMC7518121 DOI: 10.3389/fphys.2020.01103] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 08/10/2020] [Indexed: 12/17/2022] Open
Abstract
Cardiac physiology of fish models is an emerging field given the ease of genome editing and the development of transgenic models. Several studies have described the cardiac properties of zebrafish (Denio rerio). The goldfish (Carassius auratus) belongs to the same family as the zebrafish and has emerged as an alternative model with which to study cardiac function. Here, we propose to acutely study electrophysiological and systolic Ca2+ signaling in intact goldfish hearts. We assessed the Ca2+ dynamics and the electrophysiological cardiac function of goldfish, zebrafish, and mice models, using pulsed local field fluorescence microscopy, intracellular microelectrodes, and flash photolysis in perfused hearts. We observed goldfish ventricular action potentials (APs) and Ca2+ transients to be significantly longer when compared to the zebrafish. The action potential half duration at 50% (APD50) of goldfish was 370.38 ± 8.8 ms long, and in the zebrafish they were observed to be only 83.9 ± 9.4 ms. Additionally, the half duration of the Ca2+ transients was also longer for goldfish (402.1 ± 4.4 ms) compared to the zebrafish (99.1 ± 2.7 ms). Also, blocking of the L-type Ca2+ channels with nifedipine revealed this current has a major role in defining the amplitude and the duration of goldfish Ca2+ transients. Interestingly, nifedipine flash photolysis experiments in the intact heart identified whether or not the decrease in the amplitude of Ca2+ transients was due to shorter APs. Moreover, an increase in temperature and heart rate had a strong shortening effect on the AP and Ca2+ transients of goldfish hearts. Furthermore, ryanodine (Ry) and thapsigargin (Tg) significantly reduced the amplitude of the Ca2+ transients, induced a prolongation in the APs, and altogether exhibited the degree to which the Ca2+ release from the sarcoplasmic reticulum contributed to the Ca2+ transients. We conclude that the electrophysiological properties and Ca2+ signaling in intact goldfish hearts strongly resembles the endocardial layer of larger mammals.
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Affiliation(s)
- Maedeh Bazmi
- Quantitative Systems Biology Program, School of Natural Sciences, University of California, Merced, Merced, CA, United States
| | - Ariel L Escobar
- Department of Bioengineering, School of Engineering, University of California, Merced, Merced, CA, United States
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Michel MC, Michel-Reher MB, Hein P. A Systematic Review of Inverse Agonism at Adrenoceptor Subtypes. Cells 2020; 9:E1923. [PMID: 32825009 PMCID: PMC7564766 DOI: 10.3390/cells9091923] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 08/16/2020] [Accepted: 08/18/2020] [Indexed: 12/18/2022] Open
Abstract
As many, if not most, ligands at G protein-coupled receptor antagonists are inverse agonists, we systematically reviewed inverse agonism at the nine adrenoceptor subtypes. Except for β3-adrenoceptors, inverse agonism has been reported for each of the adrenoceptor subtypes, most often for β2-adrenoceptors, including endogenously expressed receptors in human tissues. As with other receptors, the detection and degree of inverse agonism depend on the cells and tissues under investigation, i.e., they are greatest when the model has a high intrinsic tone/constitutive activity for the response being studied. Accordingly, they may differ between parts of a tissue, for instance, atria vs. ventricles of the heart, and within a cell type, between cellular responses. The basal tone of endogenously expressed receptors is often low, leading to less consistent detection and a lesser extent of observed inverse agonism. Extent inverse agonism depends on specific molecular properties of a compound, but inverse agonism appears to be more common in certain chemical classes. While inverse agonism is a fascinating facet in attempts to mechanistically understand observed drug effects, we are skeptical whether an a priori definition of the extent of inverse agonism in the target product profile of a developmental candidate is a meaningful option in drug discovery and development.
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Affiliation(s)
- Martin C. Michel
- Department of Pharmacology, Johannes Gutenberg University, 55131 Mainz, Germany;
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Retana Moreira L, Rodríguez Serrano F, Osuna A. Extracellular vesicles of Trypanosoma cruzi tissue-culture cell-derived trypomastigotes: Induction of physiological changes in non-parasitized culture cells. PLoS Negl Trop Dis 2019; 13:e0007163. [PMID: 30789912 PMCID: PMC6383987 DOI: 10.1371/journal.pntd.0007163] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 01/16/2019] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Trypanosoma cruzi is the obligate intracellular parasite that causes Chagas disease. The pathogenesis of this disease is a multifactorial complex process that involves a large number of molecules and particles, including the extracellular vesicles. The presence of EVs of T. cruzi was first described in 1979 and, since then, research regarding these particles has been increasing. Some of the functions described for these EVs include the increase in heart parasitism and the immunomodulation and evasion of the host immune response. Also, EVs may be involved in parasite adhesion to host cells and host cell invasion. METHODOLOGY/PRINCIPAL FINDINGS EVs (exosomes) of the Pan4 strain of T. cruzi were isolated by differential centrifugation, and measured and quantified by TEM, NTA and DLS. The effect of EVs in increasing the parasitization of Vero cells was evaluated and the ED50 was calculated. Changes in cell permeability induced by EVs were evaluated in Vero and HL-1 cardiomyocyte cells using cell viability techniques such as trypan blue and MTT assays, and by confocal microscopy. The intracellular mobilization of Ca2+ and the disruption of the actin cytoskeleton induced by EVs over Vero cells were followed-up in time using confocal microscopy. To evaluate the effect of EVs over the cell cycle, cell cycle analyses using flow cytometry and Western blotting of the phosphorylated and non-phosphorylated protein of Retinoblastoma were performed. CONCLUSION/SIGNIFICANCE The incubation of cells with EVs of trypomastigotes of the Pan4 strain of T. cruzi induce a number of changes in the host cells that include a change in cell permeability and higher intracellular levels of Ca2+ that can alter the dynamics of the actin cytoskeleton and arrest the cell cycle at G0/G1 prior to the DNA synthesis necessary to complete mitosis. These changes aid the invasion of host cells and augment the percentage of cell parasitization.
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Affiliation(s)
- Lissette Retana Moreira
- Instituto de Biotecnología, Grupo de Bioquímica y Parasitología Molecular, Departamento de Parasitología, Universidad de Granada, Granada, Spain
| | | | - Antonio Osuna
- Instituto de Biotecnología, Grupo de Bioquímica y Parasitología Molecular, Departamento de Parasitología, Universidad de Granada, Granada, Spain
- * E-mail:
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Jiménez MAV, Nascimento JHM, Monnerat G, Maciel L, Paiva CN, Pedrosa RC, Campos de Carvalho AC, Medei E. Autoantibodies with beta-adrenergic activity from chronic chagasic patients induce cardiac arrhythmias and early afterdepolarization in a drug-induced LQT2 rabbit hearts. Int J Cardiol 2017; 240:354-359. [PMID: 28320606 DOI: 10.1016/j.ijcard.2017.02.066] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Revised: 02/07/2017] [Accepted: 02/13/2017] [Indexed: 02/08/2023]
Abstract
BACKGROUND Cardiac arrhythmias are one of the main causes of death in ChCP and other dilated cardiomyopathies. Previous studies demonstrated that ventricular arrhythmias are associated with the presence of autoantibodies with beta-adrenergic activity, Ab-β. OBJECTIVES The aim of this study was to investigate whether Ab-β, present in chronic chagasic patients (ChCP), induce cardiac arrhythmias in the pharmacological type-2 long QT syndrome model (LQTS-2). METHODS/RESULTS The LQTS2 was established by perfusion of Tyrode saline solution with a potassium channel blocker E-4031 (5μM) in isolated rabbit hearts or in rabbit cardiac strips, in order to record ECG or action potential, respectively. Autoantibodies from ChCP activating (Ab-β) or not (Ab-NR) cardiac beta 1-adrenergic receptors were used. Ab-β, but not Ab-NR, were able to significantly shorten QT, QTc and increase Tpeak-Tend interval in the LQTS-2. A positive correlation between higher QTc and Tpeak-Tend was found after Ab-β perfusion in the same model. In addition, in the LQTS-2 model, in almost 75% (11/15) of the hearts perfused with Ab-β, ventricular and atrio-ventricular electrical disturbances were observed. Atenolol abolished all Ab-β-induced arrhythmias. Ab-β, when perfused in a cellular LQTS-2, drastically reduced the action potential duration and evoked early afterdepolarization (EAD's), while Ab-NR did not modulate the AP properties in the LQTS-2. CONCLUSION The results indicate that Ab-β were able to induce cardiac arrhythmias and EAD's. This phenomenon can explain, at least in part, the cellular mechanism of Ab-β-induced arrhythmias. Furthermore, atenolol is effective for the treatment of Ab-β-induced arrhythmias.
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Affiliation(s)
| | - José H M Nascimento
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Gustavo Monnerat
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Leonardo Maciel
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Claudia N Paiva
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Roberto Coury Pedrosa
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | | | - Emiliano Medei
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
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Rodríguez-Angulo HO, Toro-Mendoza J, Marques JA, Concepción JL, Bonfante-Cabarcas R, Higuerey Y, Thomas LE, Balzano-Nogueira L, López JR, Mijares A. Evidence of reversible bradycardia and arrhythmias caused by immunogenic proteins secreted by T. cruzi in isolated rat hearts. PLoS Negl Trop Dis 2015; 9:e0003512. [PMID: 25647069 PMCID: PMC4315581 DOI: 10.1371/journal.pntd.0003512] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Accepted: 01/02/2015] [Indexed: 12/03/2022] Open
Abstract
Rationale Chagas cardiomyopathy, caused by the protozoan Trypanosoma cruzi, is characterized by alterations in intracellular ion, heart failure and arrhythmias. Arrhythmias have been related to sudden death, even in asymptomatic patients, and their molecular mechanisms have not been fully elucidated. Objective The aim of this study is to demonstrate the effect of proteins secreted by T. cruzi on healthy, isolated beating rat heart model under a non-damage-inducing protocol. Methods and Results We established a non-damage-inducing recirculation-reoxygenation model where ultrafiltrate fractions of conditioned medium control or conditioned infected medium were perfused at a standard flow rate and under partial oxygenation. Western blotting with chagasic patient serum was performed to determine the antigenicity of the conditioned infected medium fractions. We observed bradycardia, ventricular fibrillation and complete atrioventricular block in hearts during perfusion with >50 kDa conditioned infected culture medium. The preincubation of conditioned infected medium with chagasic serum abolished the bradycardia and arrhythmias. The proteins present in the conditioned infected culture medium of >50 kDa fractions were recognized by the chagasic patient sera associated with arrhythmias. Conclusions These results suggest that proteins secreted by T. cruzi are involved in Chagas disease arrhythmias and may be a potential biomarker in chagasic patients. Chagas disease, caused by the parasite Trypanosoma cruzi, is an endemic disease of Latin-American countries, affecting an estimated 8 million people in 21 countries. It is spread by the bite of triatomine reduvid bug. Due to immigration towards non-endemic regions, the disease can spread and affect people around the world via blood transfusions. Infection usually occurs in childhood, and some patients may develop acute myocarditis; however, most remain asymptomatic for many years before chronic cardiac and/or gastrointestinal manifestations appear. Chagas disease is characterized by an acute phase, which is generally asymptomatic, or oligosymptomatic, an indeterminate phase, which may persist for several years, and a chronic phase in which dilated cardiomyopathy and arrhythmias are primarily observed and sudden death may occur. Once heart failure develops, death usually occurs within several years. In this work, we demonstrate the pathophysiological role of proteins secreted by T. cruzi on cardiac arrhythmias. The antigenicity of these fractions was tested by an immunological test using chagasic patients’ sera associated with arrhythmias. We showed that perfusion of the proteins secreted by T. cruzi, in an isolated beating rat heart model, induced cardiac arrhythmias such as bradycardia and complete atrioventricular block.
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Affiliation(s)
- Héctor O. Rodríguez-Angulo
- Laboratorio de Fisiología de Parásitos, Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas, Caracas, Venezuela
| | - Jhoan Toro-Mendoza
- Centro de Estudios Interdisciplinarios de la Física. Instituto Venezolano de Investigaciones Científicas, Caracas, Venezuela
| | - Juan A. Marques
- Servicio de Cardiología, Instituto de Medicina Tropical, Universidad Central de Venezuela, Caracas, Venezuela
| | - Juan L. Concepción
- Laboratorio de Enzimología de Parásitos, Departamento de Biología, Facultad de Ciencias, Universidad de Los Andes, Mérida, Venezuela
| | - Rafael Bonfante-Cabarcas
- Unidad de Investigaciones en Bioquímica, Decanato de Ciencias de la Salud, Universidad Centroccidental “Lisandro Alvarado”, Barquisimeto, Venezuela
| | - Yoliver Higuerey
- Servicio de Cultivos de Células y Tejidos, Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas, Caracas, Venezuela
| | - Luz E. Thomas
- Laboratorio de Fisiología Molecular Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas, Caracas, Venezuela
| | - Leandro Balzano-Nogueira
- Unidad de Agronomía y Soberanía Agroalimentaria, Instituto de Estudios Avanzados (IDEA), Caracas, Venezuela
| | - José R. López
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, California, United States of America
| | - Alfredo Mijares
- Laboratorio de Fisiología de Parásitos, Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas, Caracas, Venezuela
- * E-mail: ,
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Daliry A, Pereira IR, Pereira-Junior PP, Ramos IP, Vilar-Pereira G, Silvares RR, Lannes-Vieira J, Campos De Carvalho AC. Levels of circulating anti-muscarinic and anti-adrenergic antibodies and their effect on cardiac arrhythmias and dysautonomia in murine models of Chagas disease. Parasitology 2014; 141:1769-78. [PMID: 25093253 DOI: 10.1017/s0031182014001097] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
SUMMARY Antibodies (Ab) recognizing G-protein coupled receptors, such as β 1 and β 2 adrenergic (anti-β 1-AR and anti-β 2-AR, respectively) and muscarinic cholinergic receptors (anti-M2-CR) may contribute to cardiac damage, however their role in chronic chagasic cardiomyopathy is still controversial. We describe that Trypanosoma cruzi-infected C3H/He mice show increased P and QRS wave duration, and PR and QTc intervals, while the most significant ECG alterations in C57BL/6 are prolonged P wave and PR interval. Echocardiogram analyses show right ventricle dilation in infected animals of both mouse lineages. Analyses of heart rate variability (HRV) in chronically infected C3H/He mice show no alteration of the evaluated parameters, while C57BL/6 infected mice display significantly lower values of HRV components, suggesting autonomic dysfunction. The time-course analysis of anti-β 1-AR, anti-β 2-AR and anti-M2-CR Ab titres in C3H/He infected mice indicate that anti-β 1-AR Ab are detected only in the chronic phase, while anti-β 2-AR and anti-M2-CR are observed in the acute phase, diminish at 60 dpi and increase again in the chronic phase. Chronically infected C57BL/6 mice presented a significant increase in only anti-M2-CR Ab titres. Furthermore, anti-β 1-AR, anti-β 2-AR and anti-M2-CR, exhibit significantly higher prevalence in chronically T. cruzi-infected C3H/He mice when compared with C57BL/6. These observations suggest that T. cruzi infection leads to host-specific cardiac electric alterations.
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Affiliation(s)
- Anissa Daliry
- Laboratório de Investigação Cardiovascular,Instituto Oswaldo Cruz,Fiocruz, Rio de Janeiro, RJ,Brazil
| | - Isabela Resende Pereira
- Laboratório de Biologia das Interações,Instituto Oswaldo Cruz,Fiocruz, Rio de Janeiro, RJ,Brazil
| | - Pedro Paulo Pereira-Junior
- Laboratório de Eletrofisiologia Cardíaca,Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, UFRJ,Rio de Janeiro,Brazil
| | - Isalira Peroba Ramos
- Laboratório de Cardiologia Celular e Molecular,Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, UFRJ,Rio de Janeiro,Brazil
| | - Glaucia Vilar-Pereira
- Laboratório de Biologia das Interações,Instituto Oswaldo Cruz,Fiocruz, Rio de Janeiro, RJ,Brazil
| | - Raquel Rangel Silvares
- Laboratório de Investigação Cardiovascular,Instituto Oswaldo Cruz,Fiocruz, Rio de Janeiro, RJ,Brazil
| | - Joseli Lannes-Vieira
- Laboratório de Biologia das Interações,Instituto Oswaldo Cruz,Fiocruz, Rio de Janeiro, RJ,Brazil
| | - Antônio Carlos Campos De Carvalho
- Laboratório de Cardiologia Celular e Molecular,Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, UFRJ,Rio de Janeiro,Brazil
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Rodríguez-Angulo H, Toro-Mendoza J, Marques J, Bonfante-Cabarcas R, Mijares A. Induction of chagasic-like arrhythmias in the isolated beating hearts of healthy rats perfused with Trypanosoma cruzi-conditioned medium. ACTA ACUST UNITED AC 2013; 46:58-64. [PMID: 23314340 PMCID: PMC3854352 DOI: 10.1590/1414-431x20122409] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Accepted: 09/03/2012] [Indexed: 11/21/2022]
Abstract
Chagas' myocardiopathy, caused by the intracellular protozoan Trypanosoma cruzi, is characterized by microvascular alterations, heart failure and arrhythmias. Ischemia and arrythmogenesis have been attributed to proteins shed by the parasite, although this has not been fully demonstrated. The aim of the present investigation was to study the effect of substances shed by T. cruzi on ischemia/reperfusion-induced arrhythmias. We performed a triple ischemia-reperfusion (I/R) protocol whereby the isolated beating rat hearts were perfused with either Vero-control or Vero T. cruzi-infected conditioned medium during the different stages of ischemia and subsequently reperfused with Tyrode's solution. ECG and heart rate were recorded during the entire experiment. We observed that triple I/R-induced bradycardia was associated with the generation of auricular-ventricular blockade during ischemia and non-sustained nodal and ventricular tachycardia during reperfusion. Interestingly, perfusion with Vero-infected medium produced a delay in the reperfusion-induced recovery of heart rate, increased the frequency of tachycardic events and induced ventricular fibrillation. These results suggest that the presence of parasite-shed substances in conditioned media enhances the arrhythmogenic effects that occur during the I/R protocol.
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Affiliation(s)
- H Rodríguez-Angulo
- Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas, Caracas, Venezuela
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Acute Clenbuterol Induces Hypotension, Atrioventricular Block and Cardiac Asystole in the Rabbit. Cardiovasc Toxicol 2012; 13:85-90. [DOI: 10.1007/s12012-012-9185-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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12
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Lee HC, Huang KTL, Wang XL, Shen WK. Autoantibodies and cardiac arrhythmias. Heart Rhythm 2011; 8:1788-95. [PMID: 21740882 DOI: 10.1016/j.hrthm.2011.06.032] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Accepted: 06/21/2011] [Indexed: 11/19/2022]
Abstract
Autoimmune diseases are associated with significant morbidity and mortality, afflicting about 5% of the US population. They encompass a wide range of disorders that affect all organs of the human body and have a predilection for women. In the past, autoimmune pathogenesis was not thought to be a major mechanism for cardiovascular disorders, and potential relationships remain understudied. However, accumulating evidence suggests that a number of vascular and cardiac conditions are autoimmune mediated. Recent studies indicate that autoantibodies play an important role in the development of cardiac arrhythmias, including atrial fibrillation, modulation of autonomic influences on heart rate and rhythm, conduction system abnormalities, and ventricular arrhythmias. This article will review the current evidence for the role of autoantibodies in the development of cardiac arrhythmias.
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Affiliation(s)
- Hon-Chi Lee
- Department of Internal Medicine, Division of Cardiovascular Diseases, Mayo Clinic Rochester, Rochester, Minnesota 55905, USA.
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Peter JC, Zipfel G, Lecourt AC, Bekel A, Hofbauer KG. Antibodies raised against different extracellular loops of the melanocortin-3 receptor affect energy balance and autonomic function in rats. J Recept Signal Transduct Res 2011; 30:444-53. [PMID: 21091037 DOI: 10.3109/10799893.2010.534485] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Melanocortin receptors (MCR) play an important role in the regulation of energy balance and autonomic function. In the present studies, we used active immunization against peptide sequences from the first and the third extracellular loop (EL1 and EL3) of the MC3R to generate selective antibodies (Abs) against this MCR subtype in rats. Immunization with the EL1 peptide resulted in Abs that enhanced the effects of the endogenous ligand α-melanocyte-stimulating hormone (α-MSH), whereas immunization with the EL3 peptide resulted in Abs acting as non-competitive antagonists. The phenotype of immunized rats chronically instrumented with telemetry transducers was studied under four different conditions: a high-fat diet was followed by standard lab chow, by fasting, and finally by an intraperitoneal injection of lipopolysaccharide (LPS). Under high-fat diet, food intake and body weight were higher in the EL3 than in the EL1 or the control group. Blood pressure was increased in EL3 rats and locomotor activity was reduced. Plasma concentrations of triglycerides, insulin, and leptin tended to rise in the EL3 group. After switching to standard lab chow, the EL1 group showed a small significant increase in blood pressure that was more pronounced and associated with an increase in heart rate during food restriction. No differences between the EL1 or the EL3 group were observed after LPS injection. These results show that immunization against the MC3R resulted in the production of Abs with positive or negative allosteric properties. The presence of such Abs induced small changes in metabolic and cardiovascular parameters.
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dos Santos DM, Talvani A, Guedes PMDM, Machado-Coelho GLL, de Lana M, Bahia MT. Trypanosoma cruzi: Genetic diversity influences the profile of immunoglobulins during experimental infection. Exp Parasitol 2008; 121:8-14. [PMID: 18848935 DOI: 10.1016/j.exppara.2008.09.012] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2007] [Revised: 09/10/2008] [Accepted: 09/18/2008] [Indexed: 10/21/2022]
Abstract
The clonal evolution model postulated for Trypanosoma cruzi predicts a correlation between the phylogenetic divergence of T. cruzi clonal genotypes and their biological properties. In the present study, the linkage between phylogenetic divergence of the parasite and IgG, IgG1, IgG2a and IgG2b response has been evaluated during the acute and chronic phases of the experimental infection. Eight laboratory-cloned stocks representative of this phylogenetic diversity and including the lineages T. cruzi I (genotypes 19 and 20), T. cruzi II (genotype 32) and T. cruzi (genotype 39) have been studied. The results showed that the pattern of humoral immune response was correlated with T. cruzi genotype, and that stocks included in genotype 20 were responsible for the high IgG response in the acute and chronic phases. Moreover, T. cruzi I lineage was more efficient in over-expressing all subclasses of specific anti-parasite IgG than either T. cruzi II or T. cruzi lineages. Curiously, the alteration in the pattern of antibodies induced by Benznidazole treatment was related to the phase of the infection but not to the genotype of the parasite. The data suggest that genotypes of T. cruzi are able to drive levels/subclasses of specific IgG, hence giving rise to further concerns about the sensitivity of serological assays in the diagnosis of human Chagas disease.
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Affiliation(s)
- Daniela Maria dos Santos
- Núcleo de Pesquisas em Ciências Biológicas', Universidade Federal de Ouro Preto, Ouro Preto, MG 35400-000, Brazil
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Lazzerini PE, Capecchi PL, Guideri F, Acampa M, Selvi E, Bisogno S, Galeazzi M, Laghi-Pasini F. Autoantibody-mediated cardiac arrhythmias: mechanisms and clinical implications. Basic Res Cardiol 2007; 103:1-11. [PMID: 17999027 DOI: 10.1007/s00395-007-0686-8] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2007] [Accepted: 10/11/2007] [Indexed: 11/28/2022]
Abstract
Cardiac arrhythmias, including conduction defects and tach- yarrhythmias, represent an important source of morbidity and mortality in industrialized countries. Among the different pathophysiological mechanisms involved in the arrhythmogenesis, an inappropriate activation of the immune system represents a field of recent increasing interest. In fact, a large amount of studies suggest that specific autoantibody may be significantly involved in the pathogenesis of cardiac arrhythmias not only in the course of systemic autoimmune disease, but also in a number of rhythm disorders currently classified as "idiopathic." Although the strongest evidence concerns the relationship between anti-Ro/SSA antibodies and the development of congenital heart block in foetus and newborn, other specific autoantibodies demonstrated the aptitude to affect directly the myocardial tissue, thus producing interference in its bioelectric activity thereby leading to rhythm disorders, also life-threatening. The identification of an immunological autoantibody-mediated mechanism opens new perspectives in the treatment and prevention of cardiac arrhythmias in such patients, including the use of immunosuppressive agents and/or the removal of autoantibodies by immuno-adsorption technique.
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Affiliation(s)
- Pietro Enea Lazzerini
- Department of Clinical Medicine and Immunological Sciences, Division of Clinical Immunology, University of Siena, Siena, Italy.
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