Abstract 14883: Low Dose Intravenous AAV9 Mediated Transduction of cBIN1 Lasts at Least Six Months in Minipig Hearts

Abstract

Introduction: Heart failure (HF) is a highly morbid disease with few treatment options that are designed to benefit heart muscle. In individual cardiomyocytes, HF is associated with disrupted t-tubule microdomains, limiting organization of the calcium handling machinery and cardiac function. Microdomain disruption is caused by reduced transcription of cardiac bridging integrator 1 (cBIN1), which can be restored by gene therapy to rescue HF. In a minipig model of non-ischemic HF, we found low dose intravenous delivery of cBIN1 gene therapy is efficacious for at least 6 months. However, it is not known how long the exogenous cBIN1 transgene persists in minipig hearts. Hypothesis: AAV9-cBIN1 transduction in minipig hearts can last for months Methods: 8-10 months old Yucatan minipigs with tachycardia-induced HF received a dose of PBS or AAV9-CMV-cBIN1-V5 (6x10 11 vg/kg, i.v. ). Weekly blood work was obtained to evaluate liver and renal function. Animals were terminated 6 months after injection and tissue samples were obtained from heart and other organs for histopathology and gene expression analysis. rtPCR was used to quantify exogenous mouse cBIN1-V5 gene using a probe detecting V5 and endogenous cBIN1 using a probe specific for porcine cBIN1 gene. Results: Throughout the 6-month period, no organ dysfunction was noted by blood test, or with histopathology at 6 months. At 6 months, ΔΔCt results of V5/HPRT1 indicate that AAV9 effectively transduces cBIN1-V5 (24.1 ± 5.4 fold above PBS) in hearts without detectible transduction elsewhere (Figure 1). ΔCt results of V5/cBIN1 (porcine) indicate that exogenous cBIN1-V5 expresses at 20.9 ± 1.8 % of endogenous cBIN1 gene in minipig hearts which is the level of cBIN1 overexpression needed to restore cardiac function. Conclusions: A single low dose intravenous therapy of AAV9-cBIN1 can reach efficacious levels for at least 6 months in minipig hearts without transduction in other organs.