Simultaneous assessment of calcium handling and contractility dynamics in isolated ventricular myocytes of a rat model of post-acute isoproterenol-induced cardiomyopathy

Copyright © 2019 Elsevier Ltd. All rights reserved..

Stress-induced cardiomyopathy (SIC) results from a profound catecholaminergic surge during strong emotional or physical stress. SIC is characterized by acute left ventricular apex hypokinesia, in the absence of coronary arteries occlusion, and can lead to arrhythmias and acute heart failure. Although, most SIC patients recover, the process could be slow, and recurrence or death may occur. Despite that the SIC common denominator is a large catecholamine discharge, the pathophysiological mechanism is incompletely understood. It is thought that catecholamines have direct cytotoxicity on apical ventricular myocytes (VM), which have the highest β-adrenergic receptors density, and whose overstimulation might cause acute Ca2+ overload and oxidative stress, causing death in some VM and stunning others. Rodents receiving acute isoproterenol (ISO) overdose (OV) mimic SIC development, however, they have not been used to simultaneously assess Ca2+ handling and contractility status in isolated VM, which might explain ventricular hypokinesia. Therefore, treating rats with a single ISO-OV (67 mg/kg body weight), we sought out to characterize, with confocal imaging, Ca2+ and shortening dynamics in Fluo-4-loaded VM, during the early (1-5 days) and late post-acute phases (15 days). We found that ISO-OV VM showed contractile dysfunction; blunted shortening with slower force development and relaxation. These correlated with Ca2+ mishandling; blunted Ca2+ transient, with slower time to peak and SR Ca2+ recovery. SR Ca2+ content was low, nevertheless, diastolic Ca2+ sparks were more frequent, and their duration increased. Contractility and Ca2+ dysfunction aggravated or remained altered over time, explaining slow recovery. We conclude that diminished VM contractility is the main determinant of ISO-OV hypokinesia and is mostly related to Ca2+ mishandling.

Medienart:

E-Artikel

Erscheinungsjahr:

2020

Erschienen:

2020

Enthalten in:

Zur Gesamtaufnahme - volume:86

Enthalten in:

Cell calcium - 86(2020) vom: 25. März, Seite 102138

Sprache:

Englisch

Beteiligte Personen:

Pérez-Treviño, Perla [VerfasserIn]
Sepúlveda-Leal, José [VerfasserIn]
Altamirano, Julio [VerfasserIn]

Links:

Volltext

Themen:

Aftercontraction
Calcium
Calcium signaling
Cell shortening
Isoproterenol
Journal Article
L628TT009W
Research Support, Non-U.S. Gov't
Ryanodine receptors type 2
SY7Q814VUP
Takotsubo cardiomyopathy
Ventricular hypokinesia

Anmerkungen:

Date Completed 01.06.2021

Date Revised 01.06.2021

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1016/j.ceca.2019.102138

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM304395080