Successful Reduction of Neointimal Hyperplasia on Stainless Steel Coronary Stents by Titania Nanotexturing - PubMed (original) (raw)

Successful Reduction of Neointimal Hyperplasia on Stainless Steel Coronary Stents by Titania Nanotexturing

Aleena Mary Cherian et al. ACS Omega. 2020.

Abstract

Bare metal stents (BMSs) of stainless steel (SS) were surface engineered to develop nanoscale titania topography using a combination of physical vapor deposition and thermochemical processing. The nanoleafy architecture formed on the stent surface remained stable and adherent upon repeated crimping and expansion, as well as under flow. This titania nanoengineered stent showed a preferential proliferation of endothelial cells over smooth muscle cells in vitro, which is an essential requirement for improving the in vivo endothelialization, with concurrent reduction of intimal hyperplasia. The efficacy of this surface-modified stent was assessed after implantation in rabbit iliac arteries for 8 weeks. Significant reduction in neointimal thickening and thereby in-stent restenosis with complete endothelial coverage was observed for the nanotextured stents, compared to BMSs, even without the use of any antiproliferative agents or polymers as in drug-eluting stents. Nanotexturing of stents did not induce any inflammatory response, akin to BMSs. This study thus indicates the effectiveness of a facile titania nanotopography on SS stents for coronary applications and the possibility of bringing this low-priced material back to clinics.

Copyright © 2020 American Chemical Society.

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Conflict of interest statement

The authors declare no competing financial interest.

Figures

Figure 1

Figure 1

(A) SEM images of the nanotextured SS TNL stent at different magnifications showing uniformity in nanotexturing over the entire surface. (B) AFM images confirming the nanoleafy architecture on SS TNL. (C) EDAX measurements demonstrating the presence of titanium and oxygen on SS TNL.

Figure 2

Figure 2

SEM images of (A) bare SS and (B) SS TNL stents at different magnifications after completion of 20 million cycles under flow. (C) Balloon expansion profiles of bare and nanotextured SS TNL stents.

Figure 3

Figure 3

Live–dead fluorescence images of ECs seeded on (A) bare SS and (C) SS TNL stents at 6 [A(i),C(i)], 24 [A(ii),C(ii)], and 72 h [A(iii),C(iii)] and SMCs seeded on (B) bare SS and (D) SS TNL stents at 6 [B(i),D(i)], 24 [B(ii),D(ii)], and 72 h [B(iii),D(iii)].

Figure 4

Figure 4

Angiogram and ultrasound images of bare [A(i),B(i)] and SS TNL [C(i),D(i)] stents on the day of implantation and after 8 weeks prior to euthanasia [A(ii),B(ii) for bare; C(ii),D(ii) for SS TNL]. Arrows in the angiogram point to the stented site in the artery. The value for the blood flow velocity of the respective animal is depicted in the ultrasound panel.

Figure 5

Figure 5

H&E images of (A) bare and (B) SS TNL stented vessels at 4× [A(i),B(i)], 10× [A(ii),B(ii)], and 20× [A(iii),B(iii)] magnifications.

Figure 6

Figure 6

Histomorphometric analysis showing the (A) lumen area (mm2), (B) neointimal area (mm2), (C) neointimal thickness (mm), (D) restenosis (%), (E) inflammation score, and (F) injury score of the bare and nanotextured SS TNL stent-implanted vessel sections.

Figure 7

Figure 7

SEM images of [A(i–iii)] bare SS and [B(i–iii)] nanotextured SS TNL stent-implanted arteries at different magnifications and representative immunofluorescent en face stained images of wheat germ agglutinin on ECs in the [C(i)] bare and [C(ii)] SS TNL stented artery at a depth of 2 μm from the luminal surface (scale bar: 10 μm).

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