Adeno-associated virus serotype 9 administered systemically after reperfusion preferentially targets cardiomyocytes in the infarct border zone with pharmacodynamics suitable for the attenuation of left ventricular remodeling.
BACKGROUND
Adeno-associated virus serotype 9 (AAV9) vectors provide efficient and uniform gene expression to normal myocardium following systemic administration, with kinetics that approach steady-state within 2-3 weeks. However, as a result of the delayed onset of gene expression, AAV vectors have not previously been administered intravenously after reperfusion for post-infarct gene therapy applications. The present study evaluated the therapeutic potential of post-myocardial infarction gene delivery using intravenous AAV9.


METHODS
AAV9 vectors expressing firefly luciferase, enhanced green fluorescent protein (eGFP) or extracellular superoxide dismutase genes from the cardiac troponin-T (cTnT) promoter (AcTnTLuc, AcTnTeGFP, AcTnTEcSOD) were employed. AcTnTLuc was administered intravenously at 10 min and at 1, 2 and 3 days post-ischemia/reperfusion (IR), and the kinetics of luciferase expression were assessed with bioluminescence imaging. AcTnTeGFP was used to evaluate the distribution of eGFP expression. High-resolution echocardiography was used to evaluate the effects of AcTnTEcSOD on left ventricular (LV) remodeling when injected 10 min post-IR.


RESULTS
Compared to sham animals, luciferase expression at 2 days after vector administration was elevated by four-, 24-, 210- and 213-fold in groups injected at 10 min, 1 day, 2 days and 3 days post-IR, respectively. The expression of cTnT-driven eGFP was strongest in cardiomyocytes bordering the infarct zone. In the efficacy study of EcSOD, post-infarct LV end-systolic and end-diastolic volumes at days 14 and 28 were significantly smaller in the EcSOD group compared to the control.


CONCLUSIONS
Systemic administration of AAV9 vectors after IR both elevates and accelerates gene expression that preferentially targets cardiomyocytes in the border zone with pharmacodynamics suitable for the attenuation of LV remodeling.
Department of Biomedical Engineering, University of Virginia, Charlottesville, VA, USA.
Prasad R
PR
Konkalmatt
Feng
F
Wang
Bryan A
BA
Piras
Yaqin
Y
Xu
Daniel M
DM
O'Connor
Ronald J
RJ
Beyers
Frederick H
FH
Epstein
Brian H
BH
Annex
John A
JA
Hossack
Brent A
BA
French
D000818:Animals; D000229:Dependovirus / Q000235:genetics*; D015870:Gene Expression; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D049452:Green Fluorescent Proteins / Q000235:genetics; D008156:Luciferases / Q000235:genetics; D051379:Mice; D008810:Mice, Inbred C57BL; D009203:Myocardial Infarction / Q000235:genetics / Q000628:therapy*; D017202:Myocardial Ischemia / Q000235:genetics / Q000628:therapy; D015425:Myocardial Reperfusion; D015428:Myocardial Reperfusion Injury / Q000235:genetics / Q000628:therapy; D032383:Myocytes, Cardiac / Q000187:drug effects*; D012016:Reference Values; D019076:Transgenes; D020257:Ventricular Remodeling / Q000235:genetics*
C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; D008156:Luciferases