Myocardial gene delivery using molecular cardiac surgery with recombinant adeno-associated virus vectors in vivo

Abstract

We use a novel technique that allows for closed recirculation of vector genomes in the cardiac circulation using cardiopulmonary bypass, referred to here as molecular cardiac surgery with recirculating delivery (MCARD). We demonstrate that this platform technology is highly efficient in isolating the heart from the systemic circulation in vivo. Using MCARD, we compare the relative efficacy of single-stranded (ss) adeno-associated virus (AAV)6, ssAAV9 and self-complimentary (sc)AAV6-encoding enhanced green fluorescent protein, driven by the constitutive cytomegalovirus promoter to transduce the ovine myocardium in situ. MCARD allows for the unprecedented delivery of up to 48 green fluorescent protein genome copies per cell globally in the sheep left ventricular (LV) myocardium. We demonstrate that scAAV6-mediated MCARD delivery results in global, cardiac-specific LV gene expression in the ovine heart and provides for considerably more robust and cardiac-specific gene delivery than other available delivery techniques such as intramuscular injection or intracoronary injection; thus, representing a potential, clinically translatable platform for heart failure gene therapy.

Potential of gene therapy as a treatment for heart failure

“…Recently, White et al demonstrated an extremely high transduction efficiency in the majority of cardiomyocytes in sheep while minimizing collateral organ exposure using a retrograde recirculation method during cardiopulmonary bypass surgery (28). Retrograde coronary infusion has been shown to be safe, when performed by a trained and experienced surgeon.…”

Advantages of Catheter-Based Adenoviral Delivery of Genes to the Heart for Studies of Cardiac Disease

“…White et al reported a novel surgical procedure (MCARD) that allowed for closed recirculation of AAV vectors in the cardiac circulation using cardiopulmonary bypass in sheep (White et al, 2011). This approach resulted in highly efficient, cardiac specific gene transfer using the scAAV6 vector.…”

Gene Therapy in Cardiovascular Disease

“…In murine and rodent models single stranded (ss) AAV6, self-complementary (sc) AAV6 and ssAAV9 are capable of long term expression after transference of genetic material to the cardiomyocytes, however it has not been reproduced in large animals. Recently it has been proposed that the highest levels of expression in large animals, are obtained using scAAV6 vectors, delivered through surgical methods (White et al, 2011).…”

“…The system in which the greater effectiveness of transference has been observed, consist of perfusion of the myocardium by surgical methods, a technique known as Molecular Cardiac Surgery with Recirculating Delivery (MCARD); this consists in the establishment of conventional cardiopulmonary bypass, with isolation of the heart circulation and retrograde perfusion through the coronary sinus. MCARD allows performing surgical procedures in the heart while the transference of genetic material is occurring (Hayase et al, 2005;Katz et al, 2010;Raake et al, 2004;White et al, 2011). An option to avoid the ectopic expression of the transferred gene is to put the expression of the transferred gene under the control of a specific cardiac promoter, as is the case of the human cardiac calsequestrin gene (hCasq2) (Reyes-Juarez et al, 2007).…”