Gene Delivery to Pig Coronary Arteries from Stents Carrying Antibody-Tethered Adenovirus

Abstract

Deployment of coronary stents to relieve atherosclerotic obstruction has benefitted millions of patients. However, gene therapy to prevent in-stent restenosis, while promising in experimental studies, remains a challenge. Conventional strategies for viral vector administration utilize catheters that deliver infusions of viral suspensions, which result in suboptimal localization and potentially dangerous distal spread of vector. Stent-based gene delivery may circumvent this problem. We hypothesized that site-specific delivery of adenoviral gene vectors from a stent could be achieved through a mechanism involving anti-viral antibody tethering. Stents were formulated with a collagen coating. Anti-adenoviral monoclonal antibodies were covalently bound to the collagen surface. These antibodies enabled tethering of replication defective adenoviruses through highly specific antigen-antibody affinity. We report for the first time successful stent-based gene delivery using antibody-tethered adenovirus encoding green fluorescent protein (GFP), demonstrating efficient and highly localized gene delivery to arterial smooth muscle cells in both cell culture and pig coronary arteries. Overall arterial wall transduction efficiency in pigs was 5.9 ± 1.1% of total cells. However, neointimal transduction was more than 17% of total cells in this region. Importantly, when specific antibody was used to tether adenovirus, no distal spread of vector was detectable by PCR, in either distal organs, or in the downstream segments of the stented arteries. Control adenovirus stents, with nonspecific antibody plus adenovirus, demonstrated only a few isolated foci of transduction, and poor site-specific transduction with distal spread of vector. We conclude that a vascular stent is a suitable platform for a localizable viral vector delivery system that also prevents systemic spread of vector. Gene delivery using stent-based anti-viral antibody tethering of vectors should be suitable for a wide array of single or multiple therapeutic gene strategies.