Endothelial-cell-binding aptamer for coating of intracoronary stents

Oligonucleotides capturing CD31 endothelial cells (= aptamer) were used for coating of intracoronary stents to improve endothelialization and vascular healing.

Three different coronary stents were implanted in 9 farm-raised swine: 1) cobalt-chromium stent (CC, control stent); 2) aminoparylene-coated stent (AP, polymer); and 3) aminoparylene- and aptamer-coated stent (AA). Stent length was 18 mm, stent diameter 3 mm. Animals were restudied after 6 weeks. Minimal lumen diameter (MLD) and late loss were determined by quantitative coronary angiography. Vessel lumen, intimal proliferation and restenosis were determined by histomorphometry. Disruption of the lamina elastica interna (LEI) and inflammatory reactions were assessed in all sections.

The average MLD at baseline was 2.98 ± 0.65 mm and at follow up 2.18 ± 0.53 mm (p < 0.05, n = 27). Late loss and restenosis were smallest in CC and largest in AA (ns). Histomorphometry showed no significant differences between the three stents but there were inflammatory granulomas in 22% of all stents. A clear correlation between disruption of the LEI and inflammatory granulomas was observed.

Stents coated with endothelial-cell-capturing aptamers show similar late loss and angiographic restenosis rates as uncoated cobalt-chromium stents. Neointimal proliferation was similar in all three stents suggesting comparable proliferative potentials. Inflammatory reactions were observed in 1 of 5 of all histologic sections. In the present study, no advantage of aptamer-coating on neointimal proliferation of intracoronary stents was found.