Molecular Indices of Apoptosis Activation in Elastase‐Induced Aneurysms After Embolization with Platinum Coils

Abstract

Purpose: Endovascular occlusion of aneurysms with the use of detachable platinum coils has proved to be a safe and durable alternative to the traditional surgical clipping. The aim of the present study is to understand the mechanism of apoptosis in aneurysm embolized with platinum coils using rabbit elastase-induced aneurysm model. Materials & Methods: Elastase-induced saccular aneurysms were created at the origin of right common carotid artery in thirty rabbits. Aneurysms were allowed to mature for 8 weeks then 20 aneurysms were embolized using platinum coils by endovascular means. Ten uncoiled aneurysms were used as controls. After 2 weeks (n=10) and 4 weeks (n=10) of implantation, aneurysm samples were harvested for apoptotic studies. Results: Expression of pro-caspases-3, -8 and -9 were elevated in coiled aneurysm embolized with platinum coils at both time points when compared with uncoiled aneurysm and control left carotid artery. Cleaved caspases-3, -8 and -9 were found to be expressed only at 4 weeks after embolization. Cells within aneurysm cavity were TUNEL positive at 4 weeks only. Expression of tumor necrosis-α (TNF-α) was high in coiled aneurysm when compared with controls. There was no significant difference in the expression of Fas-ligand among groups. Decreased expression of antiapoptotic protein, Bcl-2, and increased expression of proapoptotic proteins, Bad, Bax and Bid, were observed in coiled aneurysms at both time points. Conclusion: Activation apoptosis in aneurysms after embolization with platinum coils is mediated by both TNF-α mediated-extrinsic and Bcl-2 mediated-intrinsic pathway.