Page 58 - Read Online

imaging (MRI) can be used to evaluate inflammation and Fukuhara S, Hashimoto N, Nakayama T, Sakai M, Teramoto A,
destabilization of the CA wall by utilizing ferumoxytol Tominari S, Yoshimoto T. The natural course of unruptured
uptake as a surrogate indicator of macrophage turnover. cerebral aneurysms in a Japanese cohort. N Engl J Med
2012;366:2474‑82.
More recently, Edjlali et al. found that circumferential 7. Naggara ON, Lecler A, Oppenheim C, Meder JF, Raymond J.
[18]
enhancement of the CA wall on MRI can identify CAs Endovascular treatment of intracranial unruptured aneurysms:
prone to rupture. Although our knowledge of CA a systematic review of the literature on safety with emphasis on
pathobiology has improved significantly over the 8. subgroup analyses. Radiology 2012;263:828‑35.
Kotowski M, Naggara O, Darsaut TE, Nolet S, Gevry G,
past decade, there remains much to be learned and Kouznetsov E, Raymond J. Safety and occlusion rates of surgical
tested. One challenge in determining the role of the treatment of unruptured intracranial aneurysms: a systematic review
immune system in CA pathogenesis is the phenotypic and meta‑analysis of the literature from 1990 to 2011. J Neurol
plasticity exhibited by SMCs, a unique phenomenon 9. Neurosurg Psychiatry 2013;84:42‑8.
Starke RM, Durst CR, Evans A, Ding D, Raper DM, Jensen ME,
not observed in cardiac and skeletal muscle cells. Crowley RW, Liu KC. Endovascular treatment of unruptured
In the setting of vascular injury or inflammation, wide‑necked intracranial aneurysms: comparison of dual
SMCs undergo phenotypic modulation, a process by microcatheter technique and stent‑assisted coil embolization.
J Neurointerv Surg 2015;7:256‑61.
which markers of mature SMCs are downregulated and 10. Starke RM, Turk A, Ding D, Crowley RW, Liu KC, Chalouhi N,
markers of inflammatory cells, such as macrophages, Hasan DM, Dumont AS, Jabbour P, Durst CR, Turner RD. Technology
are upregulated. [19] Given the inability of conventional developments in endovascular treatment of intracranial aneurysms.
immunohistochemical staining methods to identify J Neurointerv Surg 2014. [DOI: 10.1136/neurintsurg‑2014‑011475].
transdifferentiated SMCs, evaluation of SMC epigenetic 11. Hasan DM, Mahaney KB, Brown RD Jr, Meissner I, Piepgras DG,
Huston J, Capuano AW, Torner JC. Aspirin as a promising agent
signatures and SMC lineage tracing studies are for decreasing incidence of cerebral aneurysm rupture. Stroke
necessary to accurately assess the contribution of 2011;42:3156‑62.
SMCs to vascular lesions, such as CAs. [20] Thus, the 12. Nuki Y, Tsou TL, Kurihara C, Kanematsu M, Kanematsu Y,
respective roles of cells of SMC and myeloid lineage Hashimoto T. Elastase‑induced intracranial aneurysms in
hypertensive mice. Hypertension 2009;54:1337‑44.
in CA formation, progression, and rupture remains 13. Starke RM, Raper DM, Ding D, Chalouhi N, Owens GK, Hasan DM,
incompletely defined. [21] Medel R, Dumont AS. Tumor necrosis factor‑α modulates cerebral
aneurysm formation and rupture. Transl Stroke Res 2014;5:269‑77.
Despite the current limitations in our understanding 14. Peña‑Silva RA, Chalouhi N, Wegman‑Points L, Ali M, Mitchell I,
Pierce GL, Chu Y, Ballas ZK, Heistad D, Hasan D. Novel role
of CA pathogenesis, the future of CA translational for endogenous hepatocyte growth factor in the pathogenesis of
and clinical research is promising. In this special intracranial aneurysms. Hypertension 2015;65:587‑93.
issue of Neuroimmunology and Neuroinflammation 15. Peña Silva RA, Kung DK, Mitchell IJ, Alenina N, Bader M,
on the topic of “The Role of Inflammation in Cerebral Santos RA, Faraci FM, Heistad DD, Hasan DM. Angiotensin 1‑7
reduces mortality and rupture of intracranial aneurysms in mice.
Aneurysms”, we have assembled a collection of articles Hypertension 2014;64:362‑8.
from renowned experts in the field of cerebrovascular 16. Starke RM, Chalouhi N, Jabbour PM, Tjoumakaris SI, Gonzalez LF,
disease, and attempt to lift the veil on the pathobiology Rosenwasser RH, Wada K, Shimada K, Hasan DM, Greig NH,
of intracranial aneurysms. Owens GK, Dumont AS. Critical role of TNF‑α in cerebral aneurysm
formation and progression to rupture. J Neuroinflammation
2014;11:77.
REFERENCES 17. Hasan D, Chalouhi N, Jabbour P, Dumont AS, Kung DK,
Magnotta VA, Young WL, Hashimoto T, Winn HR, Heistad D. Early
1. Brown RD Jr, Broderick JP. Unruptured intracranial aneurysms: change in ferumoxytol‑enhanced magnetic resonance imaging signal
epidemiology, natural history, management options, and familial suggests unstable human cerebral aneurysm: a pilot study. Stroke
screening. Lancet Neurol 2014;13:393‑404. 2012;43:3258‑65.
2. Hop JW, Rinkel GJ, Algra A, van Gijn J. Case‑fatality rates and 18. Edjlali M, Gentric JC, Régent‑Rodriguez C, Trystram D, Hassen WB,
functional outcome after subarachnoid hemorrhage: a systematic Lion S, Nataf F, Raymond J, Wieben O, Turski P, Meder JF,
review. Stroke 1997;28:660‑4. Oppenheim C, Naggara O. Does aneurysmal wall enhancement on
3. Mayer SA, Kreiter KT, Copeland D, Bernardini GL, Bates JE, Peery S, vessel wall MRI help to distinguish stable from unstable intracranial
Claassen J, Du YE, Connolly ES Jr. Global and domain‑specific aneurysms? Stroke 2014;45:3704‑6.
cognitive impairment and outcome after subarachnoid hemorrhage. 19. Owens GK. Regulation of differentiation of vascular smooth muscle
Neurology 2002;59:1750‑8. cells. Physiol Rev 1995;75:487‑517.
4. Nieuwkamp DJ, Setz LE, Algra A, Linn FH, de Rooij NK, Rinkel GJ. 20. Gomez D, Owens GK. Smooth muscle cell phenotypic switching in
Changes in case fatality of aneurysmal subarachnoid haemorrhage atherosclerosis. Cardiovasc Res 2012;95:156‑64.
over time, according to age, sex, and region: a meta‑analysis. Lancet 21. Starke RM, Chalouhi N, Ding D, Raper DM, Mckisic MS, Owens GK,
Neurol 2009;8:635‑42. Hasan DM, Medel R, Dumont AS. Vascular smooth muscle cells in
5. Wiebers DO, Whisnant JP, Huston J 3rd, Meissner I, Brown RD Jr, cerebral aneurysm pathogenesis. Transl Stroke Res 2014;5:338‑46.
Piepgras DG, Forbes GS, Thielen K, Nichols D, O’Fallon WM,
Peacock J, Jaeger L, Kassell NF, Kongable‑Beckman GL,
Torner JC; International Study of Unruptured Intracranial Aneurysms Cite this article as: Ding D. Inflammation of the cerebral arteries: lifting
the veil on the pathobiology of intracranial aneurysms. Neuroimmunol
Investigators. Unruptured intracranial aneurysms: natural history, Neuroinflammation 2015;2(2):49-50.
clinical outcome, and risks of surgical and endovascular treatment.
Lancet 2003;362:103‑10. Source of Support: Nil. Conflict of Interest: No.
6. UCAS Japan Investigators, Morita A, Kirino T, Hashi K, Aoki N, Received: 19-01-2015; Accepted: 25-01-2015

50 Neuroimmunol Neuroinflammation | Volume 2 | Issue 2 | April 15, 2015