Background:
Reduced activity and expression of sarcoplasmic reticulum Ca
2+
ATPase (SERCA2a) is known to occur in HF.
Method:
Our 4-month study examined the effects of SERCA2a gene transfer in a swine volume-overload HF (VO-HF) model. Using Yorkshire-Landrace swine, HF was created by severing mitral apparatus chordae to induce mitral regurgitation.
Results:
At 2 months (M), a compensated state of VO-HF was found: prolongation of the rate of isovolumic relaxation (Tau), increased left ventricular internal diameter diastolic and systolic diameters (LVIDd, LVIDs). At 2M, intracoronary injection of adeno-associated virus serotype 1 vector carrying SERCA2a under a cytomegalovirus promoter (AAV1.SERCA2a) (n = 10) vs. saline (n = 6) was performed. At 4M, gene transfer resulted in (A) positive LV inotropic effects: (dP/dt)/P, 15.5 ± 3.0 sec
− 1
SERCA2a-group vs. 21.2 ± 3.2 sec
− 1
controls; p < 0.01; (B) a favorable trend in LV lusitropic effects: Tau, 0.037 ± 0.019 vs. 0.051 ± 0.01 msec, p = 0.09; (C) improvement in LV geometry: % change in LVIDs, +15 ± 11% controls vs. −3.0 ± 10% SERCA2a-group, p < 0.01. At 4M, BNP levels remained stable in post- SERCA2a gene transfer, in contrast to the progressive rising levels among controls. Further, cardiac SERCA2a expression was significantly decreased in controls whereas it was restored to normal levels in the SERCA2a group (Figure
). Lastly, there was no histopathological evidence of myocardial inflammatory reaction or necrosis.
Conclusion:
Overexpression of SERCA2a by in vivo AAV1-mediated intracoronary gene transfer preserved systolic function, potentially prevented diastolic dysfunction and improved ventricular remodeling.
Adeno-Associated Virus Serotype 6 Capsid Tyrosine-to-Phenylalanine Mutations Improve Gene Transfer to Skeletal Muscle