How to accelerate the endothelialization of stents.

Coronary artery stenting is currently the most frequently performed percutaneous coronary intervention for the treatment of coronary artery disease. The endothelium is a single layer of endothelial cells lining the vascular wall and plays an integral part in maintaining vascular homeostasis. Stenting however causes significant injury to the vascular wall and endothelium, resulting in inflammation, repair and the development of neointimal hyperplasia. The ability of the endothelium to repair itself depends on both the migration of surrounding mature endothelial cells, and the attraction and adhesion of circulating endothelial progenitor cells (EPCs) to the injured region, which then differentiate into endothelial-like cells. Current therapies with drug-eluting stents interrupt the natural response to damage. Accelerating the reendothelialization of the damaged arterial segment following stent implantation is an attractive form of therapy as it is seen as hastening the natural process of repair. It potentially has the benefit of reducing the amount of neointimal hyperplasia and stent thrombosis. Studies have been performed to identify agents that augment the mobilisation and recruitment of EPCs to the injured area (statins, exercise, estrogen and cytokines). Other studies have looked at seeding stents with endothelial cells or EPCs. The most current approach is to coat anti-CD34 antibodies on a stent surface to attract circulating EPCs to the stent which then differentiate into endothelial-like cells. This approach is currently being tested in safety and feasibility clinical studies.