Non-elective intra-coronary stenting: are the clinical outcomes comparable to elective stenting at 6 months?

An Investigation into the Effect of Surface Roughness of Stainless Steel on Human Umbilical Vein Endothelial Cell Gene Expression

The surface properties of vascular devices dictate the initial postimplantation reactions that occur and thus the efficacy of the implantation procedure. Over the last number of years, a number of different stent designs have emerged and stents are generally polished to a mirror finish during the manufacturing procedure. This study sought to investigate the effect of stainless steel surface roughness on endothelial cell gene expression using an appropriate cell culture in vitro assay system. Stainless steel discs were roughened by shot blasting or polished by mechanical polishing. The surface roughness of the treated and untreated discs was determined by atomic force microscopy (AFM). Cells were seeded on collagen type 1 gels and left to attach for 24 h. Stainless steel discs of varying roughness were then placed in contact with the cells and incubated for 24 h. RNA extractions and quantitative real-time reverse transcriptase-polymerase chain reaction (RT-PCR) was then performed to determine the expression levels of candidate genes in the treated cells compared to suitable control cells. E-selectin and vascular cellular adhesion molecule (VCAM-1) were found to be significantly up-regulated in cells incubated with polished and roughened samples, indicating endothelial cell activation and inflammation. This study indicates that the surface roughness of stainless steel is an important surface property in the development of vascular stents.

Analysis of the effects of surface treatments on nickel release from nitinol wires and their impact on candidate gene expression in endothelial cells

Nitinol has many applications in the medical device industry, however the large amount of nickel, a known allergen and carcinogen remains a serious concern. Studies have already shown that nickel ions induce the differential expression of a range of genes, including cell adhesion molecules. This study sought to determine the level of nickel ions released from nitinol wires that had been surface treated by etching and mechanically polishing or etching and pickling compared to untreated wires and determine the biological impact of the wires on human umbilical vein endothelial cells (HUVECs) at the transcriptional level by real-time PCR. The four different wire types were incubated in media and the amount of nickel eluted after 24, 48 and 72 h was determined. HUVECs were then cultured and incubated with the four different wire types for 24 h. Cells were harvested, RNA isolated and real-time PCR was carried out to measure the expression levels of ICAM-1, VCAM-1 and E-selectin, three known inflammatory mediators, compared to control cells. E-selectin, a marker of endothelial cell injury and activation was found to be significantly up-regulated in cells incubated with wires that released the highest amount of nickel ions. Nickel ions are released from nitinol wires with certain surface characteristics and these ions have a biological effect on HUVECs in vitro.