Hassanain Toma, MD

Nakaoka H, Tajima A, Yoneyama T, Hosomichi K, Kasuya H, et al. Gene Expression Profiling Reveals Distinct Molecular Signatures Associated With the Rupture of Intracranial Aneurysm. Stroke. 2014

Nakaoka et al. sought to investigate genes associated with rupture of saccular intracranial aneurysms. They employed gene clustering methods to compare gene expression between ruptured (RIAs) and unruptured (UIAs) aneurysms.

Their analysis revealed that RIAs segregated into two distinct subgroups, with an average age of 46.6 and 80.7. Furthermore, RIAs from younger patients had 430 up-regulated, and 617 down-regulated genes, as compared to UIAs. The up-regulated genes were associated with phagocytosis, inflammatory and immune responses, while the down-regulated genes suggest mechanical weakness of aneurysm walls.

The results of this study suggest that the pathophysiology of aneurysmal rupture in young and old patients is different. Aneurysms of younger patients rupture because of elevated immune responses, while aneurysms of older patients rupture due to longstanding “wear and tear”.

The findings of Nakaoka et al. raise the question of whether statins should be given to young patients with intracranial aneurysms. Previously, the JUPITER trial demonstrated that statins are associated with a 48% relative risk reduction of total strokes in patients with normal LDL levels and elevated CRP. This is presumed to be due to the statins’ anti-inflammatory properties. Thus, the hypothesis of medically managing intracranial aneurysms with statins is not far fetched, especially since some data suggest that statin therapy is associated with a decreased expansion rate in patients with small abdominal aortic aneurysms.