title: Differences in tissue proliferation and maturation between Matrix2 and bare platinum coil embolization in experimental swine aneurysms.
abstract: OBJECTIVE
  Recanalization of post-embolization cerebral aneurysms remains a serious problem that influences treatment outcomes. Matrix2 is a bioactive, bio-absorbable, detachable coil that was developed to reduce the risk of recanalization. We examined the short-term efficacy of the Matrix2 coil system, and evaluated the temporal profile of tissue proliferation in a swine experimental aneurysm model compared with the bare platinum (BP) coil.
  
  
  METHODS
  Thirty-six experimental aneurysms were created in 18 swine. All aneurysms were tightly packed with Matrix2 or BP coils. Comparative histologic and morphologic analyses were undertaken 1, 2 and 4 weeks post-embolization.
  
  
  RESULTS
  Endothelial-like cells were observed partially lining the aneurysmal opening one week post-embolization with both coil types. At two and four weeks post-embolization, the aneurysms treated with Matrix2 coils had more extensive areas of organized thrombus than those packed with BP coils, but the numbers of functional proliferating endothelial cells identified by immunohistochemistry in the tissue were broadly comparable between the groups. Moreover, morphological analysis suggested there were more mature endothelial cells in aneurysms treated with bare platinum rather than Matrix2 coils.
  
  
  CONCLUSIONS
  Our results indicate that aneurysms embolized with Matrix2 coils build thicker scaffolds for endothelialization, but this is not necessarily evidence of earlier tissue proliferation and maturation than those embolized with BP coils. Matrix2 coils may not be superior to BP coils for preventing aneurysmal recanalization after endovascular treatment of cerebral aneurysms.
authors.affiliation: Department of Neurosurgery, Juntendo University School of Medicine, Tokyo, Japan. Electronic address: ymishima@juntendo.ac.jp.
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Mitome-Mishima
authors.affiliation: Department of Neurosurgery, Juntendo University School of Medicine, Tokyo, Japan; Department of Neuroendovascular Therapy, Juntendo University School of Medicine, Tokyo, Japan.
authors.forename: Hidenori
authors.initials: H
authors.lastname: Oishi
authors.affiliation: Department of Neurosurgery, Juntendo University School of Medicine, Tokyo, Japan.
authors.forename: Munetaka
authors.initials: M
authors.lastname: Yamamoto
authors.affiliation: Department of Neurosurgery, Juntendo University Nerima Hospital, Tokyo, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Yatomi
authors.affiliation: Department of Neurosurgery, Juntendo University Urayasu Hospital, Chiba, Japan.
authors.forename: Senshu
authors.initials: S
authors.lastname: Nonaka
authors.affiliation: Department of Neurology, Juntendo University Urayasu Hospital, Chiba, Japan.
authors.forename: Nobukazu
authors.initials: N
authors.lastname: Miyamoto
authors.affiliation: Department of Neurology, Juntendo University Urayasu Hospital, Chiba, Japan.
authors.forename: Takao
authors.initials: T
authors.lastname: Urabe
authors.affiliation: Department of Neurosurgery, Juntendo University School of Medicine, Tokyo, Japan.
authors.forename: Hajime
authors.initials: H
authors.lastname: Arai
mesh_terms: D000818:Animals; D001672:Biocompatible Materials; D049109:Cell Proliferation; D004621:Embolization, Therapeutic / Q000295:instrumentation* / Q000379:methods; D042783:Endothelial Cells / Q000502:physiology*; D057510:Endovascular Procedures; D005260:Female; D002532:Intracranial Aneurysm / Q000473:pathology* / Q000601:surgery / Q000628:therapy*; D008297:Male; D010984:Platinum; D013552:Swine
chemical_list: D001672:Biocompatible Materials; D010984:Platinum
keywords: Endothelial cell proliferation; Matrix2 coil; Swine experimental aneurysm