Inhibition of late sodium current attenuates ionic arrhythmia mechanism in ventricular myocytes expressing LaminA-N195K mutation.
Heart Rhythm
; 13(11): 2228-2236, 2016 11.
Article
in En
| MEDLINE
| ID: mdl-27498076
ABSTRACT
BACKGROUND:
Lamin A and C are nuclear filament proteins encoded by the LMNA gene. Mutations in the LMNA gene cause many congenital diseases known as laminopathies, including Emery-Dreifuss muscular dystrophy, Hutchinson-Gilford progeria syndrome, and familial dilated cardiomyopathy (DCM) with conduction disease. A missense mutation (N195K) in the A-type lamins results in familial DCM and sudden arrhythmic death.OBJECTIVE:
The purpose of this study was to investigate the ion current mechanism of arrhythmia and DCM caused by the LaminA-N195K variant.METHODS:
A homozygous mouse line expressing the Lmna-N195K mutation (LmnaN195K/N195K) that exhibited arrhythmia, DCM, and sudden death was used. Using whole cell patch-clamp technique, we measured action potential duration (APD), Na+ currents (INa) in ventricular myocytes isolated from LmnaN195K/N195K, and wild-type mice.RESULTS:
Both peak and late INa were significantly (P <.05) increased in LmnaN195K/N195K ventricular myocytes. Similarly, LmnaN195K/N195K ventricular myocytes exhibited significant (P <.005) prolongation of APD (time to 50% [APD50] and 90% [APD90] repolarization) and triggered activity. Acute application of ranolazine inhibited late INa, shortened APD, and abolished triggered activity in LmnaN195K/N195K ventricular myocytes.CONCLUSION:
Inhibition of late INa may be an effective therapy in preventing arrhythmia in patients with LmnaN195K mutation-related DCM.Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Arrhythmias, Cardiac
/
Cardiomyopathy, Dilated
/
Sodium Channels
/
Myocytes, Cardiac
/
Ranolazine
Type of study:
Etiology_studies
Limits:
Animals
Language:
En
Journal:
Heart Rhythm
Year:
2016
Document type:
Article