1. ¹Molecular Cardiology, Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, USA
2. ²Division of Cardiovascular Research, St Elizabeth's Medical Center, Tufts University School of Medicine, Boston, MA, USA
3. ³Surface Solutions Labs Inc., Carlisle, MA, USA

Correspondence: Dr K Walsh, Molecular Cardiology, Whitaker Cardiovascular Institute, Boston University School of Medicine, 715 Albany St W611, Boston, MA 02118, USA

Received 8 July 2002; Accepted 3 February 2003.

Abstract

Metallic stents coated with a polyurethane emulsion containing plasmid DNA were implanted in rabbit iliac arteries to evaluate transgene delivery and expression in the vessel wall. The expression of the plasmid-encoded marker genes, -galactosidase, luciferase and green fluorescence protein (GFP), were evaluated at 7 days after implantation. In all cases, plasmid transfer was confined to the vessel wall at the site of stent implantation, plasmid DNA was not observed in vessel segments immediately proximal or distal to the stent and dissemination of plasmid DNA to lung, liver or spleen was not observed. Expression of transgenes occurred only in vessel segments in contact with the stent and analysis of the GFP expression pattern revealed a high frequency of marker protein-positive cells occurring at or near the luminal surface. The extent of transgene expression was dependent upon the quantity of DNA loaded onto the stent and no signal was detected in vessel segments that received polymer-coated stents lacking plasmid DNA. Of significance, colocalization studies identified transgene expression not only in vascular smooth muscle cells but also in macrophages. Hence, polymer-coated stents provide a new capability for transgene delivery to immune cells that are believed to contribute to the development of in-stent restenosis.