High Wall Shear Incites Cerebral Aneurysm Formation and Low Wall Shear Stress Propagates Cerebral Aneurysm Growth

Abstract

This review discusses mechanisms for the development of cerebral aneurysms. Endothelial cells exhibit a variety of structural and functional changes when they come into contact with normal laminar flow. In response to laminar shear stress, endothelial cells modify their potassium ion channels, go through cytoskeletal rearrangements and shape modifications and create prostacyclin. In cerebral arteries, aneurysmal dilatation most frequently starts at locations with substantial wall shear stress, which include arterial bifurcations and vascular branch sites, where blood flow abruptly switches to turbulent flow. At this point, high shear stress frequently arises, placing increased strain on the vasculature. As the vascular branch points and arterial bifurcations are the initial sites of cerebral aneurysm genesis, this helps confirm the role of high wall shear stress in the development of cerebral aneurysms. Low wall shear stress increases the initial proinflammatory effect already present in the vasculature, which furthers the formation of cerebral aneurysms. In fact, regions of aneurysmal regions with low wall shear stress grow more quickly and are more prone to rupture compared to regions with high wall shear stress. Therefore, it seems plausible to assume that turbulent blood flow inside a dilated cerebral aneurysm causes low wall shear stress, thereby encouraging aneurysmal growth.

J Neurol Res. 2023;13(1):1-11
doi: https://doi.org/10.14740/jnr749