Magnetic capture of blood outgrowth endothelial cells to the luminal surface of magnetizable stent-grafts promotes healing in a porcine pseudoaneurysm model

Stent-grafts are endovascular devices used to treat many arterial conditions including carotid artery pseudoaneurysms. Stent-grafts are composed of a metal stent backbone covered by a synthetic membrane to form a conduit. Their deployment results in a large surface area of synthetic material in contact with blood, which increases the risk of thrombosis and occlusion of the device. The more rapidly the blood contacting surface becomes covered with an endothelium, acting as a barrier between the device and blood flow, the lower the risk of these complications. One approach to promote the rapid endothelialization of a stent-graft is with magnetic cell capture. In the current work, we develop magnetizable stent-grafts and generate autologous blood outgrowth endothelial cells from peripheral blood. The cells are labeled with superparamagnetic iron oxide nanoparticles to impart magnetic properties. The ability of the magnetic stent-grafts to occlude pseudoaneurysms and magnetically capture delivered cells is investigated relative to non-magnetic stent-graft controls in a porcine carotid pseudoaneurysm model. We demonstrated that at the study endpoints, the control and magnetic stent-grafts had occluded 7/9 and 9/9 of the pseudoaneurysms, respectively. Histological analysis demonstrated a higher degree of magnetic cell capture, endothelialization, and luminal tissue coverage in the magnetic stent-grafts compared to their non-magnetic controls. At the study endpoints, 2/9 control stent-grafts had completely thrombosed while 0/9 magnetic stent-grafts had. In conclusion, the magnetic stent-grafts facilitated the magnetic capture of blood outgrowth endothelial cells, which appeared to improve biological outcomes relative to non-magnetic stent-graft controls. Statement of significance: Stent-grafts are devices deployed in the arteries to restore blood flow. They are composed of a stent backbone covered by a membrane of synthetic material to form a conduit. Their deployment results in a large surface area of synthetic material in contact with blood. This increases the risk of thrombosis and the narrowing and occlusion of the device. The more rapidly the blood contacting surface becomes covered with an endothelium, acting as a barrier between the device and blood flow, the lower the risk of these complications. In the current study, we investigate an approach to magnetically adhere endothelial cells to the surface of magnetizable stent-grafts to promote the rapid development of an endothelium in a pig model.