title: Evidence of reversible bradycardia and arrhythmias caused by immunogenic proteins secreted by T. cruzi in isolated rat hearts.
abstract: BACKGROUND
  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.
  
  
  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.
authors: Laboratorio de Fisiología de Parásitos, Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas, Caracas, Venezuela.
authors: Héctor O
authors: HO
authors: Rodríguez-Angulo
authors: Centro de Estudios Interdisciplinarios de la Física. Instituto Venezolano de Investigaciones Científicas, Caracas, Venezuela.
authors: Jhoan
authors: J
authors: Toro-Mendoza
authors: Servicio de Cardiología, Instituto de Medicina Tropical, Universidad Central de Venezuela, Caracas, Venezuela.
authors: Juan A
authors: JA
authors: Marques
authors: Laboratorio de Enzimología de Parásitos, Departamento de Biología, Facultad de Ciencias, Universidad de Los Andes, Mérida, Venezuela.
authors: Juan L
authors: JL
authors: Concepción
authors: Unidad de Investigaciones en Bioquímica, Decanato de Ciencias de la Salud, Universidad Centroccidental "Lisandro Alvarado", Barquisimeto, Venezuela.
authors: Rafael
authors: R
authors: Bonfante-Cabarcas
authors: Servicio de Cultivos de Células y Tejidos, Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas, Caracas, Venezuela.
authors: Yoliver
authors: Y
authors: Higuerey
authors: Laboratorio de Fisiología Molecular Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas, Caracas, Venezuela.
authors: Luz E
authors: LE
authors: Thomas
authors: Unidad de Agronomía y Soberanía Agroalimentaria, Instituto de Estudios Avanzados (IDEA), Caracas, Venezuela.
authors: Leandro
authors: L
authors: Balzano-Nogueira
authors: Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, California, United States of America.
authors: José R
authors: JR
authors: López
authors: Laboratorio de Fisiología de Parásitos, Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas, Caracas, Venezuela.
authors: Alfredo
authors: A
authors: Mijares
mesh_terms: D000818:Animals; D015153:Blotting, Western; D001919:Bradycardia / Q000469:parasitology* / Q000503:physiopathology; D002598:Chagas Cardiomyopathy / Q000469:parasitology / Q000503:physiopathology*; D002522:Chlorocebus aethiops; D005260:Female; D006321:Heart / Q000503:physiopathology*; D006333:Heart Failure / Q000469:parasitology / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D015800:Protozoan Proteins / Q000276:immunology* / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D014349:Trypanosoma cruzi / Q000472:pathogenicity; D014709:Vero Cells
chemical_list: D015800:Protozoan Proteins
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