Impact of magnetic targeting on BM-SMC uptake into vessel wall

Improved BM-SMC uptake into the vessel wall upon magnetic targeting was assessed ex vivo within matrix-disrupted porcine carotids (Lampire Biological Labs). The arteries were de-endothelialized using a guide wire, intraluminally infused with 20 U/mL porcine pancreatic elastase (Sigma-Aldrich) using a Scimed 5F catheter (SCIMED Life System) for 20 min at 37°C to disrupt the aortal elastic matrix, and then rinsed with sterile PBS.

SPION-BM-SMCs (1 × 10⁶ cells/mL) were labeled with VivoTrack 680 (Perkin Elmer; 0.5 mg/mL, 15 min) and then infused into the carotid lumen at 15 × 10⁶ cells/mL using a Scimed 5F catheter, with the distal end clamped. BM-SMCs were infused into control carotids. The test artery alone was exposed to a permanent NdFeB magnet (CMS Magnetics) for 40 min.¹³ The arteries were then flushed repeatedly with PBS to remove loosely adherent cells. Image J^® analysis of whole tissue images (Bruker Xtreme^®) quantified relative fluorescence across the vessel length. Results were plotted as mean fluorescence versus axial distance from point of cell infusion. The carotids were opened lengthwise and fluorescence signal distribution visualized using a laser-based scanning system (LI-COR Odyssey^®).