Local delivery of c7E3 Fab (Reopro) from polymer-coated coronary stents into human saphenous vein ex vivo

c7E3 Fab (ReoPro, abciximab) is a potent antiplatelet agent with inhibitory effects on smooth muscle cell migration. It is capable of reducing the incidence of coronary events and the need for revascularisation at six months and beyond. Delivering agents loaded onto a stent allows prolonged site-specific delivery of a drug to achieve a high local concentration whilst minimising systemic toxicity and side effects. The aim of this study was to investigate the release of c7E3 from polymer coated stents into human saphenous vein ex vivo. Methods: Polymer-coated pre-mounted GRII stents were immersed into a 2mg/ml solution of c7E3 for 24 hours. Coated stents were deployed into segments of human saphenous vein, using a 3.5mm PTCA balloon (10 atm, 1 minute). The vein was tied into a chamber where culture medium was circulated through the vein lumen for 24 hours. The vein was then removed from the circuit and the ends of vein proximal and distal to the stent were removed. The region of vein surrounding the stent was cut longitudinally to remove the stent. The segments of vein were snap frozen and transverse sections were cut and mounted on glass slides. Immuno-histochemical staining for c7E3 was performed using an indirect labelling method with diaminobenzidine to detect antibody binding. Results: c7E3 was only detected in segments of vein which had been balloon-injured prior to stent deployment. Positive staining was seen along the luminal surface of the vessel wall in the segment of vein which had directly surrounded the stent. Some staining was also seen in the medial layer. No positive staining was seen in the segments of vein proximal and distal to the stent. Conclusion: c7E3 Fab can be delivered into the vessel wall of pre-injured human vascular tissue via a polymer-coated stent.