Intracellular signaling pathways and size, shape, and rupture history of human intracranial aneurysms

Elisa Laaksamo, Manasi Ramachandran, Juhana Frösen, Riikka Tulamo, Marc Baumann, Robert M. Friedlander, Robert E. Harbaugh, Juha Hernesniemi, Mika Niemelä, Madhavan L. Raghavan, Aki Laakso

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20 Scopus citations

Abstract

Background: Size and morphological features are associated with intracranial aneurysm (IA) rupture. The cellular mechanisms of IA development and rupture are poorly known. Objective: We studied the expression and phosphorylation of different intracellular signaling molecules in the IA wall compared with IA morphological features to understand better the cellular pathways involved in IA development and wall degeneration. Methods: Nine ruptured and 17 unruptured human IA samples were collected intraoperatively. The expression levels and phosphorylation state of 3 mitogen-activated protein kinases (c-Jun N-terminal kinase [JNK], p38, extracellular signal-regulated kinase [ERK]), Bcl-2 antagonist of cell death (Bad), mammalian target of rapamycin (mTOR), cyclic AMP response element binding protein (CREB), and Akt were determined by Western blotting. The localization of signaling proteins was determined by immunofluorescence. From 3-dimensional segmentation of computed tomography angiographic data, size and shape indexes were calculated. Results: We found a 5-fold difference in phospho-Bad levels between ruptured and unruptured IAs. Phospho-mTOR was downregulated 2.5-fold in ruptured IAs. Phospho-p54 JNK, phospho-p38, and phospho-Akt levels correlated positively with IA size. Phospho-CREB levels were significantly associated with nonsphericity and ellipticity indexes. Phospho-Akt and phospho-p38 correlated negatively with undulation index. Conclusion: The signaling pathway profile (apoptosis, cell proliferation, stress signaling) differs between ruptured and unruptured IAs and is associated with IA geometry. Our results increase the knowledge of IA development and wall degeneration.

Original languageEnglish (US)
Pages (from-to)1565-1572
Number of pages8
JournalNeurosurgery
Volume70
Issue number6
DOIs
StatePublished - Jun 1 2012

All Science Journal Classification (ASJC) codes

  • Surgery
  • Clinical Neurology

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    Laaksamo, E., Ramachandran, M., Frösen, J., Tulamo, R., Baumann, M., Friedlander, R. M., Harbaugh, R. E., Hernesniemi, J., Niemelä, M., Raghavan, M. L., & Laakso, A. (2012). Intracellular signaling pathways and size, shape, and rupture history of human intracranial aneurysms. Neurosurgery, 70(6), 1565-1572. https://doi.org/10.1227/NEU.0b013e31824c057e