• Haruka Miyata, Hirohiko Imai, Hirokazu Koseki, Kampei Shimizu, Yu Abekura, Mieko Oka, Takakazu Kawamata, Tetsuya Matsuda, Kazuhiko Nozaki, Shuh Narumiya, and Tomohiro Aoki.
• 1Department of Molecular Pharmacology, Research Institute, and.
• J. Neurosurg. 2020 Sep 1; 133 (3): 789799789-799.

ObjectiveSubarachnoid hemorrhage (SAH) has a poor outcome despite modern advancements in medical care. The development of a novel therapeutic strategy to prevent rupture of intracranial aneurysms (IAs) or a novel diagnostic marker to predict rupture-prone lesions is thus mandatory. Therefore, in the present study, the authors established a rat model in which IAs spontaneously rupture and examined this model to clarify histopathological features associated with rupture of lesions.MethodsFemale Sprague Dawley rats were subjected to bilateral ovariectomy; the ligation of the left common carotid, the right external carotid, and the right pterygopalatine arteries; induced systemic hypertension; and the administration of a lysyl oxidase inhibitor.ResultsAneurysmal SAH occurred in one-third of manipulated animals and the locations of ruptured IAs were exclusively at a posterior or anterior communicating artery (PCoA/ACoA). Histopathological examination using ruptured IAs, rupture-prone IAs induced at a PCoA or ACoA, and IAs induced at an anterior cerebral artery-olfactory artery bifurcation that never ruptured revealed the formation of vasa vasorum as an event associated with rupture of IAs.ConclusionsThe authors propose the contribution of a structural change in an adventitia, i.e., vasa vasorum formation, to the rupture of IAs. Findings from this study provide important insights about the pathogenesis of IAs.

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