| dc.description.abstract | Embolic coils have become a valuable tool for occluding brain aneurysms to reduce the occurrence of hemorrhagic strokes and the associated high mortality and morbidity rates, but this strategy is still limited by high rates of recanalization and retreatment. Devices utilizing shape memory polymer foam for occlusion applications have demonstrated potential to enhance occlusion and improve healing associated with the treatment, which is expected to decrease recanalization rates. Extensive, rigorous testing is required to demonstrate that new devices, such as those utilizing the shape memory polymer foam, will be safe and effective in order to enable clinical translation. In this dissertation, we use established and novel methods to evaluate biological responses to a shape memory polymer foam-coated coil device designed for treating brain aneurysms.
Long-term implantation studies in the rabbit elastase aneurysm model demonstrated improved healing relative to standard bare platinum coil device controls. Additionally, the devices did not induce a chronic inflammatory response. In vitro cytocompatibility of the degradation products from this device was evaluated using novel methods, and it was observed that the degradation products are unlikely to cause a cytotoxic response. This is consistent with the aforementioned and other in vivo studies that have assessed the biocompatibility of this shape memory polymer foam. Finally, potential mechanisms for the improved healing associated with shape memory polymer foams were investigated using immunostaining and qPCR techniques with in vivo and in vitro samples. The macrophage phenotypes associated with the inflammatory response to the devices were found to vary in in vitro and in vivo testing at early timepoints.
The findings from these studies support the continued evaluation of the shape memory polymer foam-coated coil devices as a valuable treatment option that may improve outcomes in endovascular occlusion procedures. Additionally, novel methods developed here may allow biocompatibility evaluation of polymer degradation products that could not have been directly evaluated previously. | en |
