Biodegradable polyglycolide endovascular coils promote wall thickening and drug delivery in a rat aneurysm model

OBJECTIVE: We designed biodegradable polyglycolide coils (BPCs) and compared the histopathological response to the coils with that to platinum Guglielmi detachable coils (GDCs), after insertion into ligated common carotid arteries (CCAs) of adult rats. BPCs were also tested for use in local drug delivery. METHODS: Segments (4-mm) of unmodified BPCs, unmodified GDCs, or BPCs coated with Type I bovine collagen and recombinant human vascular endothelial growth factor-165 (500 mug/ml) were inserted into ligated CCAs of adult rats for 14 days, and specimens were compared with contralateral CCA control specimens. RESULTS: Arterial segments with BPCs exhibited substantially increased wall thickening, compared with GDCs (0.33 mm versus 0.10 mm, P < 0.005), which reduced the luminal diameter by 40%, relative to untreated contralateral control specimens (P < 0.05, n = 6). Arterial segments with BPCs also exhibited a marked reduction (P < 0.05, n = 6) in luminal area (0.72 <plus/minus> 0.93 mm(2)), with marked cellular proliferation within the coil diameter, indicating coil integration. Arterial segments with collagen/recombinant human vascular endothelial growth factor-coated BPCs also exhibited a marked 2.9-fold increase (P < 0.005, n = 5) in wall thickness (0.29 +/- 0.11 mm) and a 34% reduction in luminal diameter, compared with contralateral control vessels. There was marked proliferation of cells within the coil lumen of vessels treated with BPCs with collagen/recombinant human vascular endothelial growth factor. CONCLUSION: In this feasibility study, BPCs enhanced the vascular response of CCA segments, compared with GDCs, and were also suitable for local protein delivery to the vessel lumen, under conditions of stasis and arterial pressurization of vascular cells.