Heart rate reduction after genetic ablation of L-type Cav1.3 channels induces cardioprotection against ischemia-reperfusion injury

Viviana Delgado-Betancourt; Kroekkiat Chinda; Pietro Mesirca; Christian Barrère; Aurélie Covinhes; Laura Gallot; Anne Vincent; Isabelle Bidaud; Sarawut Kumphune; Joël Nargeot; Christophe Piot; Kevin Wickman; Matteo Elia Mangoni; Stéphanie Barrère-Lemaire

doi:10.3389/fcvm.2023.1134503

Heart rate reduction after genetic ablation of L-type Ca_v1.3 channels induces cardioprotection against ischemia-reperfusion injury

Front Cardiovasc Med. 2023 Aug 1:10:1134503. doi: 10.3389/fcvm.2023.1134503. eCollection 2023.

Authors

Viviana Delgado-Betancourt^{1

2}, Kroekkiat Chinda^{1

3}, Pietro Mesirca^{1

2}, Christian Barrère^{1

2}, Aurélie Covinhes^{1

2}, Laura Gallot^{1

2}, Anne Vincent^{1

2}, Isabelle Bidaud^{1

2}, Sarawut Kumphune⁴, Joël Nargeot^{1

2}, Christophe Piot^{1

2

5}, Kevin Wickman⁶, Matteo Elia Mangoni^#^{1

2}, Stéphanie Barrère-Lemaire^#^{1

2}

Affiliations

¹ Institut de Génomique Fonctionnelle, Université Montpellier, CNRS, INSERM, Montpellier, France.
² LabEx Ion Channel Science & Therapeutics (ICST), Université de Nice, Valbonne, France.
³ Department of Physiology, Faculty of Medical Science, Naresuan University, Phitsanulok, Thailand.
⁴ Biomedical Engineering Institute (BMEi), Chiang Mai University, Chiang Mai, Thailand.
⁵ Département de Cardiologie Interventionnelle, Clinique du Millénaire, Montpellier, France.
⁶ Department of Pharmacology, University of Minnesota, Minneapolis, MN, United States.

^# Contributed equally.

Abstract

Background: Acute myocardial infarction (AMI) is the major cause of cardiovascular mortality worldwide. Most ischemic episodes are triggered by an increase in heart rate, which induces an imbalance between myocardial oxygen delivery and consumption. Developing drugs that selectively reduce heart rate by inhibiting ion channels involved in heart rate control could provide more clinical benefits. The Ca_v1.3-mediated L-type Ca²⁺ current (I_Cav1.3) play important roles in the generation of heart rate. Therefore, they can constitute relevant targets for selective control of heart rate and cardioprotection during AMI.

Objective: We aimed to investigate the relationship between heart rate and infarct size using mouse strains knockout for Ca_v1.3 (Ca_v1.3^-/-) L-type calcium channel and of the cardiac G protein gated potassium channel (Girk4^-/-) in association with the funny (f)-channel inhibitor ivabradine.

Methods: Wild-type (WT), Ca_v1.3^+/-, Ca_v1.3^-/- and Girk4^-/- mice were used as models of respectively normal heart rate, moderate heart rate reduction, bradycardia, and mild tachycardia, respectively. Mice underwent a surgical protocol of myocardial IR (40 min ischemia and 60 min reperfusion). Heart rate was recorded by one-lead surface ECG recording, and infarct size measured by triphenyl tetrazolium chloride staining. In addition, Ca_v1.3^-/- and WT hearts perfused on a Langendorff system were subjected to the same ischemia-reperfusion protocol ex vivo, without or with atrial pacing, and the coronary flow was recorded.

Results: Ca_v1.3^-/- mice presented reduced infarct size (-29%), while Girk4^-/- displayed increased infarct size (+30%) compared to WT mice. Consistently, heart rate reduction in Ca_v1.3^+/- or by the f-channel blocker ivabradine was associated with significant decrease in infarct size (-27% and -32%, respectively) in comparison to WT mice.

Conclusion: Our results show that decreasing heart rate allows to protect the myocardium against IR injury in vivo and reveal a close relationship between basal heart rate and IR injury. In addition, this study suggests that targeting Ca_v1.3 channels could constitute a relevant target for reducing infarct size, since maximal heart rate dependent cardioprotective effect is already observed in Ca_v1.3^+/- mice.

Keywords: cardioprotection; cav1.3 calcium channel; genetic model; heart rate; heart rate reduction; ischemia-reperfusion injury; myocardial infarction.

Grants and funding

The project was supported by the Fondation Leducq TNE 19CV03 FANTASY (to MM), the Agence Nationale pour la Recherche (ANR, Paris) grant ANR-2010-BLAN-1128-01 (to MM), by the Fondation de France, Paris (Cardiovasc 2008002730, to JN), the NIH (Bethesda, MD) grant R01HL105550 (to KW), and the Fundación Social la Caixa to VD-B, the “Fonds européen de développement régional” (FEDER grant #43457 to SB-L). Support from the ANR (ANR-11-LABX-0015) for the Laboratory of Excellence (Labex) “Ion Channel Science and Therapeutics” (ICST) has been provided to VD-B and LG as well as for SB-L, MM, JN, AV, CB, IB and PM. The project was also supported by the French Ambassy in Bangkok and Campus France (“Programme Jeunes chercheurs 2019” to KC) and the PHC SIAM 2020 (Project number 44928QF to SK and SB-L).