Danon disease is a rare
X-linked genetic disease resulting from LAMP2 mutations leading to defective lysosomal function.
Heart failure is the main causes of morbidity and mortality. Mice with an LAMP2-exon-6-deletion (L2Δ6), develop
cardiac hypertrophy followed by
dilated cardiomyopathy, in association with accumulation of autophagosomes,
fibrosis and oxidative stress. We investigated the effect of drugs used to treat
heart failure and of LAMP2 gene therapy on the phenotype, molecular markers and ROS in LAMP2
cardiomyopathy. L2Δ6 mice were treated with
Angiotensin II,
Ramipril,
Metoprolol or
Spironolactone. Gene therapy was delivered by IP injection of Adeno-associated-virus (AAV9) -LAMP2 vector to neonates ("AAVLAMP2-Prevention"), or at 15 weeks of age ("AAVLAMP2-Treatment").
Angiotensin II markedly aggravated the cardiac phenotype.
Ramipril and
Spironolactone were effective in attenuating
left ventricular hypertrophy and preserving the systolic function. Cardiac protection was associated with decreased autophagosome accumulation, reduced
fibrosis and oxidative stress. Gene therapy effectively attenuated autophagosome accumulation and ROS in L2Δ6 hearts, lowering
troponin release to nearly normal levels. AAVLAMP2-Prevention protected against systolic dysfunction and decreased
hypertrophy. AAVLAMP2-Treatment prevented ventricular dilatation and dysfunction but had no effect on wall thickness. We conclude that RAAS inhibitors are highly effective against
cardiomyopathy progression in an experimental mouse model of Danon's and shall be considered in human patients for this purpose until novel
therapies become clinically available.