In-vitro assays of polymer-coated stents eluting platelet glycoprotein IIb/IIIa receptor monoclonal antibody

Design, preparation and performance of a novel drug-eluting stent with multiple layer coatings

Drug-eluting stents (DESs) can effectively control the harmful effects of coronary artery disease, because of their excellent ability to reduce in-stent restenosis. However, delayed re-endothelialization and late stent thrombosis have caused concern over the safety of DESs. In this study, according to time-ordered pathological responses after stent implantation, a hierarchical multiple drug-eluting stent was designed and prepared to overcome the existing DES limitations. A platelet membrane glycoprotein IIIa monoclonal antibody (SZ-21) and a vascular endothelial growth factor (VEGF₁₂₁) were loaded into the inner coating of 316L stainless steel (316L SS) stents to inhibit thrombosis and promote re-endothelialization; rapamycin (RAPA) was loaded into the third layer to inhibit intima hyperplasia; a drug-free poly-l-lactic acid coating was located on the second and fourth layers and used as sustained release layers. The results showed that the three drugs exhibited sequential release kinetics without significant burst release. RAPA released quickly at the early stage, while SZ-21 and VEGF₁₂₁ achieved a slow and prolonged release. In vitro experiments showed that the stents had excellent hemocompatibility and anti-inflammatory properties, and promoted the proliferation and migration of endothelial cells while inhibiting the proliferation and migration of smooth muscle cells. Finally the stents were implanted in the carotid arteries of New Zealand white rabbits. In vivo results showed that compared to 316L SS stents, the multiple drug-eluting stents could accelerate re-endothelialization and inhibit thrombosis, inflammation and in-stent restenosis after 4 weeks (12.79 ± 2.45% vs. 25.27 ± 4.81%) and 12 weeks (15.87 ± 3.62% vs. 58.84 ± 6.87%). These results indicate that the novel drug-eluting stent with multiple layer coatings will have a highly potential clinical application.

Endothelialization and in-stent restenosis on the surface of glycoprotein IIIa monoclonal antibody eluting stent

Since the percutaneous transtuminal coronary angioplasty was introduced into China in 1984, this procedure has become widely accepted as an important step in coronary revascularization. This study shows the effect of the monoclonal antibody (mAb) on the platelet glycoprotein IIIa receptor during endothelialization and in-stent restenosis by implanting the mAb-eluting stents into iliac arteries of rabbits. The hard tissue cross sections of the stent-implanted arterial segments were made by polymethylmethacrylate embedding. Arterial intima proliferation was observed and analyzed. The endothelialization of the stent surface was observed using scanning electron microscope, whereas the ultrastructure of the neointima was observed using transmission electron microscope. After one month of stent implantation, the surfaces of both groups were covered by intact endothelial layers, but the neointimal areas and the ratio of stenosis were significantly lesser in the mAb-eluting stent group (p < 0.01). After 3 months, the ratio of stenosis in the mAb-eluting stent group was 14.67 ± 0.79, whereas that of the bare stent group was 21.58 ± 1.76 (p < 0.01). Therefore, the mAb eluting from the stent surface has the potential to accelerate endothelialization, prevent thrombosis formation due to the interaction of stent with blood, and decrease the stenosis ratio by inhibiting neointima proliferation.