Neonatal gene transfer of Serca2a delays onset of hypertrophic remodeling and improves function in familial hypertrophic cardiomyopathy

Familial hypertrophic cardiomyopathy (FHC) is an autosomal dominant genetic disorder linked to numerous mutations in the sarcomeric proteins The clinical presentation of FHC is highly variable but It is a major cause of sudden cardiac death in young adults with no specific treatments We tested the hypothesis that early intervention in Ca2+ regulation may prevent pathological hypertrophy and improve cardiac function in a FHC displaying increased myofilament sensitivity to Ca2+ and diastolic dysfunction A transgenic (TG) mouse model of FHC with a mutation in tropomyosin at position 180 was employed Adenoviral-Serca2a (Ad Ser) was injected into the left ventricle of 1-day-old non-transgenic (NTG) and TG mice Ad LacZ was injected as a control Serca2a protein expression was significantly increased in NTG and TG hearts injected with Ad Ser for up to 6 weeks Compared to TG Ad LacZ hearts the TG-Ad Ser hearts showed improved whole heart morphology Moreover there was a significant decline in ANF and beta MHC expression Developed force in isolated papillary muscle from 2- to 3 week-old TG Ad Ser hearts was higher and the response to isoproterenol (ISO) improved compared to TG Ad LacZ muscles In situ hemodynamic measurements showed that by 3 months the TG-Ad Ser hearts also had a significantly improved response to ISO compared to TG-Ad LacZ hearts The present study strongly suggests that Serca2a expression should be considered as a potential target for gene therapy in FHC Moreover our data imply that development of FHC can be successfully delayed if therapies are started shortly after birth (C) 2010 Elsevier Ltd All rights reserved