Endovascular Treatment of Aneurysms: Healing Mechanisms in a Swine Model Are Associated with Increased Expression of Matrix Metalloproteinases, Vascular Cell Adhesion Molecule-1, and Vascular Endothelial Growth Factor, and Decreased Expression of Tissue Inhibitors of Matrix Metalloproteinases

Gross photographs showing a thin to moderately thick membranous tissue at the neck of a 2-week aneurysm (A) and a thick membranous tissue at the neck of a 12-week aneurysm (B).

Histologic evaluation of harvested aneurysms at 2 weeks (A–C) and 12 weeks (D and E).

A, Microphotograph showing attenuated inflammatory tissue within the aneurysm dome (H&E, original magnification ×100).

B, Microphotograph showing attenuated spindle cells associated with some inflammatory cells within the aneurysm dome (H&E, original magnification ×150).

C, Microphotograph showing that all spindle cells within the aneurysm dome are positive for SMA (immunohistochemistry, antibody for α-SMA, original magnification ×150).

D, Microphotograph showing highly vascularized fibrous tissue within the aneurysm dome (H&E, original magnification ×60).

E, Microphotograph showing attenuated inflammatory cells associated with numerous thin-walled vessels within the aneurysm dome (H&E, original magnification ×100).

A representative gelatin zymogram of MMP-2 and MMP-9 from pigs at 2 weeks (A) and 12 weeks (B) after embolization. Densitometric analysis of gelatin zymogram of pro-MMP-9 (C), active-MMP-9 (D), pro-MMP-2 (E), and active-MMP-2 (F) at both 2-week and 12-week time points. Labels a–g represent P < .05 compared with FA, JV, PPA, and DPA at 2 weeks (a); FA, JV, PPA, and DPA at 12 weeks (b); PA at 2 weeks (c); PA at 12 weeks (d); the neck at 2 weeks (e); the neck at 12 weeks (f); and the dome at 2 weeks (g).