Stent angioplasty has led to a recent paradigm shift in the care of arteriosclerotic vascular disease. Gene delivery stents represent a promising future therapy that will likely result in even greater benefits from stent- interventions. This program wil investigate a novel direction for the next period of support, gene delivery stents with direct attachment of adeno-associated viral vectors (AAV) to metallic stent surfaces using hydrolysable linkers. At this time, AAV are in the forefront in human gene therapy clinical trials because of their low risks of toxicity and long lasting transgene expression. Hypothesis: Long term gene therapy for prevention of in-stent restenosis (ISR) through enhanced arterial regeneration can be achieved with gene delivery stent-AAV formulations encoding extracellular superoxide dismutase (SOD3).
Aim 1. Investigate the pharmacokinetics (PK) and efficacy of AAV-gene delivery stents using the rat carotid stent angioplasty model. AAV gene delivery stents will utilize a three component complex-an AAV, a hydrolysable crosslinker (HC) reactive with both AAV, and the 3rd component, a water soluble polyallylamine bisphosphonate with latent thiol groups (PABT) for coordination binding and chemical activation of bare metal stent surfaces.
Sub aim 1 A: Cell culture model studies of gene delivery stents: AAV-HC-PABT-stent complexes will be investigated in vitro using arterial smooth muscle cell cultures to mimic the gene delivery stent interaction with the arterial wall with the specific emphasis on local delivery mechanisms and dose ranges of both reporter and SOD3 AAV.
Sub aim 1 B: in vivo PK & biodistribution--We will characterize local delivery, pharmacokinetics, biodistribution and transgene expression with AAV-gene delivery stents. Luciferase (Luc) reporter studies will use quantitative in vivo imaging, investigating the time course of expression with varying AAV dosing.
Sub aim 1 C: Efficacy experiments: Our AAV-SOD-3 therapeutic study will investigate a dose range with endpoints including inhibition of ISR, re-endothelialization of injured arteries, and effects on biomarkers of inflammation and oxidative stress.
Aim 2. Investigate AAV-gene delivery stent efficacy for ISR prevention in atherosclerotic arteries, using a double injury model in Watanabe rabbits.
Sub aim 2 A: will involve a study of AAV-eGFP, AAV-SOD3 and BMS with 14 day post-procedure stent retrievals with GFP detection endpoints to study delivery mechanisms, pharmacokinetics and biodistribution.
Sub aim 2 B: The reporter data will be used to guide dosages for a therapeutic study investigating the efficacy of AAV-SOD3 attached to stent surfaces as an anti-restenotic intervention.
Arterial disease affecting either the heart, brain or extremities, is the leading cause of death and disability in the United States. This proposal will study a novel approach for gene therapy for arterial disease, using expandable stents to both open obstructed arteries and to deliver improved treatments using gene vectors. The proposed experiments will be carried out in small animals, with the hope that positive results will lead to new and improved clinical therapies.
