RT Journal Article SR Electronic T1 Parent artery-initiated and stent-mediated neointima formation in a rat saccular side wall model JF Journal of NeuroInterventional Surgery JO J NeuroIntervent Surg FD BMJ Publishing Group Ltd. SP 1258 OP 1263 DO 10.1136/neurintsurg-2021-018297 VO 14 IS 12 A1 Wanderer, Stefan A1 GrĂ¼ter, Basil Erwin A1 Boillat, Gwendoline A1 Sivanrupan, Sivani A1 Rey, Jeannine A1 Catalano, Kristina A1 vonGunten, Michael A1 Widmer, Hans Rudolf A1 Andereggen, Lukas A1 Marbacher, Serge YR 2022 UL http://jnis.bmj.com/content/14/12/1258.abstract AB Background Unlike clipping that forms an immediate barrier of blood flow into intracranial aneurysms, endovascular treatments rely on thrombus organization and neointima formation. Therefore, a continuous endothelial cell layer is crucial to prevent blood flow in the former aneurysm. This study investigates the origin of endothelial cells in the neointima of endovascular treated aneurysms, specifically whether cells from the parent artery play a role in neointima formation.Methods In male rats, decellularized and vital side wall aneurysms were treated by coil (n=16) or stent embolization (n=15). The cell tracer CM-Dil dye was injected into the clamped aorta before aneurysm suture to mark initial endothelial cells in the parent artery and enable tracking of their proliferation during follow-up. Aneurysms were analyzed for growth, thrombus formation, and recurrence. Histological evaluation followed with cell counts for specific regions-of-interest.Results During follow-up, none of the 31 aneurysms ruptured. Macroscopic residual perfusion was observed in 12/16 rats after coiling and in 1/15 after stenting. Amounts of CM-Dil +cells in coiled versus stented decellularized aneurysms significantly decreased in the thrombus on day 7 (p=0.01) and neointima on day 21 (p=0.04). For vital aneurysms, the number of CM-Dil +cells in the neointima on day 21 showed no significant difference.Conclusions Healing patterns were worse in coil-treated than stent-treated aneurysms. Cell migration forming a neointima seemed mainly dependent on the adjacent vessel in decellularized aneurysms, but appeared buoyed by recruitment from aneurysm wall cells in vital aneurysms. Therefore, a cell-rich parent artery might be crucial.All data relevant to the study are included in the article or uploaded as supplementary information. NA.