Comparison of endothelial cells grown on different stent materials

Abstract

We compared the behavior of endothelial cells grown on stent materials. Human umbilical vein endothelial cells (HUVEC) were seeded (200 or 800 cells/mm(2)) onto different metallic sheets, including 316 stainless steel (low carbon; 316LSS), nitinol, and 316LSS coated with TiN or TiO(2). Cells seeded onto tissue culture-treated polystyrene dish coated with gelatin were used as controls. Forty-eight hours later, the cells were examined by Western blotting, immunofluorescence microscopy, and scanning electron microscopy (SEM). The results showed that for either seeding values, the levels of cellularity on TiN and TiO(2) are comparable or higher, and those on 316LSS and nitinol are lower compared to the controls (p < 0.05). SEM demonstrated that cells are well-attached on the metallic surface with various amount of cellular processes. In metals seeded with 800 cells/mm(2), Western blotting showed that the overlying cells expressed less amounts of endothelial nitric oxide synthase (eNOS), Von Willebrand factor (VWF), and connexin43 protein compared to the controls (p < 0.05). Immunofluorescence microscopy confirmed the results of immunoblotting. In conclusion, stent materials affect HUVEC's growth and protein expression profile. Down-regulation of eNOS, VWF, and connexin43 gap junctions is a common phenomenon in the cells growing on the examined metallic materials, suggesting the existence of endothelial dysfunction in the arterial segments containing the stents made of such materials.

Regulation of Cellular Communication by Signaling Microdomains in the Blood Vessel Wall

“…Endothelium-derived hyperpolarizing factor Edwards et al, 1998;Hutcheson et al, 1999;Yamamoto et al, 1999;Beny and Schaad, 2000;Kansui et al, 2004;Mather et al, 2005;Rath et al, 2012;Howitt et al, 2013Vascular conducted responses Kruger et al, 2002Dora et al, 2003b;Simon and McWhorter, 2003;Wolfle et al, 2007;Duling, 2008 Feedback on vasoconstriction Dora et al, 1997;Straub et al, 2011 Smooth muscle cell proliferation Chadjichristos et al, 2006;Liao et al, 2007;Johnstone et al, 2010;Zhong et al, 2012 a Smooth muscle cell differentiation Kwak et al, 2003;Chadjichristos et al, 2008;Shen et al, 2010;Gairhe et al, 2011Gairhe et al, , 2012 Endothelial cell proliferation Larson et al, 1997;Kwak et al, 2001;Yeh et al, 2006;Nakano et al, 2008;Wang et al, 2008 c Endothelial cell dysfunction Xie and Hu, 1994;Makino et al, 2008;Chadjichristos et al, 2010;Wang et al, 2012;Ebong and Depaola, 2013 Endothelial cell migration Pepper and Meda, 1992;Pepper et al, 1989;Kwak et al, 2001 a Evidence that gap junction independent pathways are involved in this regulation . b Evidence that although connexin expression and/or gap junction communication levels correlated to disease they do not appear to be directly linked...…”

Enhanced endothelial cell density on NiTi surfaces with sub-micron to nanometer roughness

“…At room temperature, NiTi is known to oxidize and form a TiO 2 fi lm on the surface. If this TiO 2 fi lm is uniform across the surface, it may be benefi cial for increasing endothelial cell functions (Yeh et al 2006). It is uncertain how our processing of the NiTi substrates in liquid nitrogen may have modifi ed this TiO 2 layer.…”

“…NiTi has both mechanical and thermal shape memory properties, and thus, a NiTi vascular stent can unfold once exposed to the convective heat fl ow of blood. The superelastic property of NiTi provides a high level of fl exibility that is advantageous for delivering the stent to the occluded vascular site (Shabalovskaya et al 2002;Yeh et al 2006). However, the ability of conventional NiTi to rapidly endothelialize upon implantation has been less than satisfactory; hence, the need for rapid endothelialization has prompted the current investigation into the benefi ts of NiTi with sub-micron to nanometer surface features.…”

“…However, amorphized NiTi may lose its shape-memory properties advantageous for vascular stent applications. Other studies simply polished NiTi sheets with different grades of metallographic papers (Wirth et al 2004;Yeh et al 2006). However, polished NiTi surfaces have been shown to increase thrombogenicity, promoting clotting and neointima formation (Armitage 2003).…”

A Survey of Surface Modification Techniques for Next-Generation Shape Memory Polymer Stent Devices

“…However, these cells express less endothelial nitric oxide synthase (eNOS), which may lead to increased endothelial cell dysfunction; this reduced eNOS activity has actually been shown to be characteristic of metals in general, modified or bare, presenting a reason for further research into non-metal implant materials [44]. Microblasting followed by reactive ion etching on metal surfaces also produces roughened, high energy surfaces that may potentially improve cell attachment [20].…”