Endothelial-cell-binding aptamer for coating of intracoronary stents.

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

Intimal proliferation and restenosis in paclitaxel-eluting stents with aminoparylene as carrier substance in swines.

BACKGROUND: Polymer as carrier substance for drugeluting stents (DES) has been accused of inducing inflammation and hypersensitivity reactions leading to restenosis and stent thrombosis. Thus, a new paclitaxel-eluting stent (PES) with aminoparylene as a carrier substance is tested in the present study. METHODS: In 10 pigs, stents were implanted in the epicardial coronary arteries: 1) bare-metal stents (BMS, control stent); 2) cobalt-chromium stents (CCS); and 3) PES. Stent length was 15 mm, and diameter was 3 mm. The animals were restudied after 6 weeks. Quantitative coronary angiography was performed at baseline and follow up. Minimum luminal diameter (MLD) and late loss were calculated in all animals. Histologic vessel lumen, intimal proliferation and restenosis were determined by morphometry. Disruption of the lamina elastica interna (LEI) and inflammatory reactions were assessed by histology. RESULTS: The MLD at baseline was 2.83 +/- 0.28 mm, and at follow up it was 2.29 +/- 0.44 (p < 0.05; n = 30). Late loss and angiographic restenosis were smallest in the CCS and largest in the PES (ns). Neointimal proliferation was similar for all 3 stents, ranging between 1.38 and 1.64 mm(2) (ns). There was a significant correlation between disruption of the LEI and inflammatory reactions. CONCLUSIONS: PTs with aminoparylene as a carrier substance show similar late loss and angiographic restenosis to that of BM and CCS. The incidence of inflammatory reactions (35% of all histologic sections) is similar in all stents, but highest in PES. The mechanism of this reaction is unclear, but may be either due to the drug itself, the disruption of the LEI or to a hypersensitivity reaction.