“New Mechanism in Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT1)”
Hosted by the Cardiac Bioelectricity and Arrhythmia Center (CBAC)
Abstract: Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a lethal genetic arrhythmia, which manifests by syncope or sudden death in children and young adults under stress conditions. Most of the identified mutations to date concern the Ca2+ release channel, the Ryanodine Receptor 2 (RyR2). Data so far have pointed to different mechanisms in different mutations, most of them with gain of function by increasing the Ca2+ sensitivity of the channel (both cytosolic and luminal), altering intramolecular interactions or its binding to FKBP12.6. We identified a mutation in the N-terminal portion of the channel (RyR2R420Q) in a Spanish family with 3 cases of sudden death in the young. In order to investigate the mechanisms involved in this mutation, we created a mice model bearing the RyR2R420Q and obtained induced pluripotent stem cells derived cardiomyocytes (hiPSC-CM) from 4 family members (2 with and 2 without the mutation, either sex). We analyzed ventricular and sinoatrial node (SAN) function using in vivo electrocardiogram recordings, and in vitro intracellular calcium measurements using confocal microscopy. Cellular electrophysiological data was obtained by patch-clamp and microelectrodes. In the seminar I will present data obtained up to that date in RyR2R420Q mice and hiPSC-CM and the conclusions on the proarythmogenic mechanisms we deduce from those data.
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