Matrix metalloproteinase-9 may play a role in recanalization and recurrence after therapeutic embolization of aneurysms or arteries

J Vasc Interv Radiol. 2007 Oct;18(10):1271-9. doi: 10.1016/j.jvir.2007.06.034.


Purpose: Matrix metalloproteinase (MMP)-9 plays various roles in vascular healing and angiogenesis. This study was conducted to determine if MMP-9 is involved in healing or recanalization after therapeutic occlusion of arteries or aneurysms.

Materials and methods: Angiographic and pathologic changes were investigated in canine bilateral venous pouch carotid aneurysms embolized with gelatin sponges with or without previous endothelial denudation, a procedure that can prevent recanalization. To assess a potential role of MMP-9, messenger RNA (mRNA) and protein were compared in denuded and nondenuded aneurysms 4, 7, and 14 days after embolization. To assess if MMP-9 is essential to arterial recanalization, transmyocardial angiography and pathologic findings were compared 14 days after carotid occlusion with platinum coils in MMP-9-knockout and wild-type mice.

Results: Denudation of the endothelial lining led to improved angiographic results at 3 weeks (P < .001). Neointimal closure of the aneurysm neck was more complete in denuded versus nondenuded aneurysms. Denudation was followed by a decrease in MMP-9 mRNA (86%, P < .05) and protein (30%, P < .05) 7 days after embolization and a decrease in von Willebrand factor compared with nondenuded aneurysms. MMP-9 immunostaining of axial sections from embolized aneurysms confirmed MMP-9-positive endothelialized clefts, which were absent in denuded aneurysms. Transmyocardial angiography and pathologic examination showed recanalization of one of nine coiled carotid arteries of MMP-9-knockout mice, compared with five of seven controls (P = .035).

Conclusions: MMP-9 may play a role in recanalization of arteries after coil occlusion and in recurrences after sponge embolization of aneurysms.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aneurysm / enzymology
  • Aneurysm / pathology
  • Aneurysm / physiopathology
  • Aneurysm / therapy*
  • Angiography
  • Animals
  • Carotid Artery Diseases / enzymology
  • Carotid Artery Diseases / pathology
  • Carotid Artery Diseases / physiopathology
  • Carotid Artery Diseases / therapy*
  • Carotid Artery, Common / enzymology*
  • Carotid Artery, Common / pathology
  • Carotid Artery, Common / physiopathology
  • Carotid Artery, Common / surgery
  • Disease Models, Animal
  • Dogs
  • Embolization, Therapeutic* / methods
  • Endothelium, Vascular / enzymology*
  • Endothelium, Vascular / pathology
  • Endothelium, Vascular / physiopathology
  • Gene Expression Regulation, Enzymologic
  • Matrix Metalloproteinase 9 / deficiency
  • Matrix Metalloproteinase 9 / genetics
  • Matrix Metalloproteinase 9 / metabolism*
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • RNA, Messenger / metabolism
  • Recurrence
  • Time Factors
  • Treatment Outcome
  • Wound Healing*
  • von Willebrand Factor / metabolism


  • RNA, Messenger
  • von Willebrand Factor
  • Matrix Metalloproteinase 9