Immobilization of basic fibroblast growth factor on a platinum microcoil to enhance tissue organization in intracranial aneurysms

Object. To enhance tissue organization in an aneurysm lumen, the authors prepared a platinum microcoil carrying basic fibroblast growth factor (bFGF) and analyzed its effectiveness in the treatment of aneurysms. Methods. Ultrathin multiorganic layers were assembled on a platinum coil through successive deposition of cationic polyethylenimine and anionic heparin, and then bFGF was immobilized through an affinity interaction with heparin. The bFGF was effectively immobilized on the surface of the platinum coil without deterioration of the coil's mechanical properties. Coil embolization of aneurysms constructed using a canine common carotid artery was performed via the endovascular approach. The aneurysms together with parent arteries were harvested 2 weeks after coil embolization. Platinum coils unmodified, coated with heparin, or immobilized with heparin and bFGF were examined. The percentage of occlusion at the aneurysm orifice in animals treated with bFGF-immobilized coils (92.99 +/- 7.94%) was significantly greater than that in animals treated with heparin-coated coils (57.26 +/- 10.76%) or unmodified coils (52.86 +/- 8.54%). The histological score of the aneurysms treated with bFGF-immobilized coils was also significantly greater than the scores in the control group. Conclusions. These results indicated that bFGF-immobilized microcoils may be beneficial in the obliteration of aneurysms.